feat: transfer MessagePort between workers (#11076)

Add support for transferring `MessagePort`s between workers.

21 files changed, 373 insertions, 346 deletions

diff --git a/cli/dts/lib.deno.shared_globals.d.ts b/cli/dts/lib.deno.shared_globals.d.ts
index 46154c64e..be35fae01 100644
--- a/cli/dts/lib.deno.shared_globals.d.ts
+++ b/cli/dts/lib.deno.shared_globals.d.ts
@@ -386,7 +386,7 @@ declare class Worker extends EventTarget {
     specifier: string | URL,
     options?: WorkerOptions,
   );
-  postMessage(message: any, transfer: ArrayBuffer[]): void;
+  postMessage(message: any, transfer: Transferable[]): void;
   postMessage(message: any, options?: PostMessageOptions): void;
   addEventListener<K extends keyof WorkerEventMap>(
     type: K,
diff --git a/cli/dts/lib.deno.worker.d.ts b/cli/dts/lib.deno.worker.d.ts
index eb8f6ebf1..7d8f6078b 100644
--- a/cli/dts/lib.deno.worker.d.ts
+++ b/cli/dts/lib.deno.worker.d.ts
@@ -68,7 +68,8 @@ declare class DedicatedWorkerGlobalScope extends WorkerGlobalScope {
     | ((this: DedicatedWorkerGlobalScope, ev: MessageEvent) => any)
     | null;
   close(): void;
-  postMessage(message: any): void;
+  postMessage(message: any, transfer: Transferable[]): void;
+  postMessage(message: any, options?: PostMessageOptions): void;
   addEventListener<K extends keyof DedicatedWorkerGlobalScopeEventMap>(
     type: K,
     listener: (
@@ -105,7 +106,8 @@ declare var onmessageerror:
   | ((this: DedicatedWorkerGlobalScope, ev: MessageEvent) => any)
   | null;
 declare function close(): void;
-declare function postMessage(message: any): void;
+declare function postMessage(message: any, transfer: Transferable[]): void;
+declare function postMessage(message: any, options?: PostMessageOptions): void;
 declare var navigator: WorkerNavigator;
 declare var onerror:
   | ((this: DedicatedWorkerGlobalScope, ev: ErrorEvent) => any)
diff --git a/cli/main.rs b/cli/main.rs
index 2586e9b60..29151f14b 100644
--- a/cli/main.rs
+++ b/cli/main.rs
@@ -125,7 +125,7 @@ fn create_web_worker_callback(
       broadcast_channel: program_state.broadcast_channel.clone(),
     };
 
-    let mut worker = WebWorker::from_options(
+    let (mut worker, external_handle) = WebWorker::from_options(
       args.name,
       args.permissions,
       args.main_module,
@@ -151,7 +151,7 @@ fn create_web_worker_callback(
     }
     worker.bootstrap(&options);
 
-    worker
+    (worker, external_handle)
   })
 }
 
diff --git a/cli/tests/workers/message_port.ts b/cli/tests/workers/message_port.ts
new file mode 100644
index 000000000..d78304a39
--- /dev/null
+++ b/cli/tests/workers/message_port.ts
@@ -0,0 +1,14 @@
+const channel = new MessageChannel();
+
+channel.port2.onmessage = (e) => {
+  channel.port2.postMessage(e.data === "2");
+  channel.port2.close();
+};
+
+self.postMessage("1", [channel.port1]);
+
+self.onmessage = (e) => {
+  const port1 = e.ports[0];
+  port1.postMessage(e.data === "3");
+  port1.close();
+};
diff --git a/cli/tests/workers/nonexistent_worker.out b/cli/tests/workers/nonexistent_worker.out
index e43b81c5f..04b9f801d 100644
--- a/cli/tests/workers/nonexistent_worker.out
+++ b/cli/tests/workers/nonexistent_worker.out
@@ -1,3 +1,3 @@
 [WILDCARD]error: Uncaught (in worker "") Cannot resolve module "file:///[WILDCARD]cli/tests/workers/doesnt_exist.js".
 error: Uncaught (in promise) Error: Unhandled error event reached main worker.
-    at Worker.#poll ([WILDCARD])
+    at Worker.#pollControl ([WILDCARD])
diff --git a/cli/tests/workers/permissions_blob_local.ts.out b/cli/tests/workers/permissions_blob_local.ts.out
index a6a34e3a2..0835777ec 100644
--- a/cli/tests/workers/permissions_blob_local.ts.out
+++ b/cli/tests/workers/permissions_blob_local.ts.out
@@ -1,4 +1,4 @@
 error: Uncaught (in worker "") Requires read access to "[WILDCARD]local_file.ts", run again with the --allow-read flag
     at blob:null/[WILDCARD]:1:0
 error: Uncaught (in promise) Error: Unhandled error event reached main worker.
-    at Worker.#poll (deno:runtime/js/11_workers.js:243:23)
+    at Worker.#pollControl ([WILDCARD])
diff --git a/cli/tests/workers/permissions_blob_remote.ts.out b/cli/tests/workers/permissions_blob_remote.ts.out
index 8bd277361..2d01458ca 100644
--- a/cli/tests/workers/permissions_blob_remote.ts.out
+++ b/cli/tests/workers/permissions_blob_remote.ts.out
@@ -1,4 +1,4 @@
 error: Uncaught (in worker "") Requires net access to "example.com", run again with the --allow-net flag
     at blob:null/[WILDCARD]:1:0
 error: Uncaught (in promise) Error: Unhandled error event reached main worker.
-    at Worker.#poll (deno:runtime/js/11_workers.js:243:23)
+    at Worker.#pollControl ([WILDCARD])
diff --git a/cli/tests/workers/permissions_data_local.ts.out b/cli/tests/workers/permissions_data_local.ts.out
index 302ab99c8..2a6be2b57 100644
--- a/cli/tests/workers/permissions_data_local.ts.out
+++ b/cli/tests/workers/permissions_data_local.ts.out
@@ -1,4 +1,4 @@
 error: Uncaught (in worker "") Requires read access to "[WILDCARD]local_file.ts", run again with the --allow-read flag
     at data:application/javascript;base64,[WILDCARD]:1:0
 error: Uncaught (in promise) Error: Unhandled error event reached main worker.
-    at Worker.#poll (deno:runtime/js/11_workers.js:243:23)
+    at Worker.#pollControl ([WILDCARD])
diff --git a/cli/tests/workers/permissions_data_remote.ts.out b/cli/tests/workers/permissions_data_remote.ts.out
index 9b0ae44cc..90677892a 100644
--- a/cli/tests/workers/permissions_data_remote.ts.out
+++ b/cli/tests/workers/permissions_data_remote.ts.out
@@ -1,4 +1,4 @@
 error: Uncaught (in worker "") Requires net access to "example.com", run again with the --allow-net flag
     at data:application/javascript;base64,aW1wb3J0ICJodHRwczovL2V4YW1wbGUuY29tL3NvbWUvZmlsZS50cyI7:1:0
 error: Uncaught (in promise) Error: Unhandled error event reached main worker.
-    at Worker.#poll (deno:runtime/js/11_workers.js:243:23)
+    at Worker.#pollControl ([WILDCARD])
diff --git a/cli/tests/workers/permissions_dynamic_remote.ts.out b/cli/tests/workers/permissions_dynamic_remote.ts.out
index e2c671c34..e68c96df1 100644
--- a/cli/tests/workers/permissions_dynamic_remote.ts.out
+++ b/cli/tests/workers/permissions_dynamic_remote.ts.out
@@ -3,4 +3,4 @@ await import("https://example.com/some/file.ts");
 ^
     at async http://localhost:4545/cli/tests/workers/dynamic_remote.ts:2:1
 [WILDCARD]error: Uncaught (in promise) Error: Unhandled error event reached main worker.
-    at Worker.#poll (deno:runtime/js/11_workers.js:243:23)
+    at Worker.#pollControl ([WILDCARD])
diff --git a/cli/tests/workers/permissions_remote_remote.ts.out b/cli/tests/workers/permissions_remote_remote.ts.out
index 8b8820c7d..5656b75a1 100644
--- a/cli/tests/workers/permissions_remote_remote.ts.out
+++ b/cli/tests/workers/permissions_remote_remote.ts.out
@@ -1,4 +1,4 @@
 error: Uncaught (in worker "") Requires net access to "example.com", run again with the --allow-net flag
     at http://localhost:4545/cli/tests/workers/static_remote.ts:2:0
 error: Uncaught (in promise) Error: Unhandled error event reached main worker.
-    at Worker.#poll (deno:runtime/js/11_workers.js:243:23)
+    at Worker.#pollControl ([WILDCARD])
diff --git a/cli/tests/workers/test.ts b/cli/tests/workers/test.ts
index 6a572b92f..b37b7aeb1 100644
--- a/cli/tests/workers/test.ts
+++ b/cli/tests/workers/test.ts
@@ -769,3 +769,56 @@ Deno.test({
     worker.terminate();
   },
 });
+
+Deno.test({
+  name: "worker with relative specifier",
+  fn: async function (): Promise<void> {
+    assertEquals(location.href, "http://127.0.0.1:4545/cli/tests/");
+    const promise = deferred();
+    const w = new Worker(
+      "./workers/test_worker.ts",
+      { type: "module", name: "tsWorker" },
+    );
+    w.onmessage = (e): void => {
+      assertEquals(e.data, "Hello, world!");
+      promise.resolve();
+    };
+    w.postMessage("Hello, world!");
+    await promise;
+    w.terminate();
+  },
+});
+
+Deno.test({
+  name: "Send MessagePorts from / to workers",
+  fn: async function (): Promise<void> {
+    const result = deferred();
+    const worker = new Worker(
+      new URL("message_port.ts", import.meta.url).href,
+      { type: "module" },
+    );
+
+    const channel = new MessageChannel();
+
+    worker.onmessage = (e) => {
+      assertEquals(e.data, "1");
+      assertEquals(e.ports.length, 1);
+      const port1 = e.ports[0];
+      port1.onmessage = (e) => {
+        assertEquals(e.data, true);
+        port1.close();
+        worker.postMessage("3", [channel.port1]);
+      };
+      port1.postMessage("2");
+    };
+
+    channel.port2.onmessage = (e) => {
+      assertEquals(e.data, true);
+      channel.port2.close();
+      result.resolve();
+    };
+
+    await result;
+    worker.terminate();
+  },
+});
diff --git a/cli/tests/workers/worker_error.ts.out b/cli/tests/workers/worker_error.ts.out
index 244e56417..4a8e92f00 100644
--- a/cli/tests/workers/worker_error.ts.out
+++ b/cli/tests/workers/worker_error.ts.out
@@ -2,4 +2,4 @@
     at foo ([WILDCARD])
     at [WILDCARD]
 error: Uncaught (in promise) Error: Unhandled error event reached main worker.
-    at Worker.#poll ([WILDCARD])
+    at Worker.#pollControl ([WILDCARD])
diff --git a/cli/tests/workers/worker_nested_error.ts.out b/cli/tests/workers/worker_nested_error.ts.out
index 244e56417..4a8e92f00 100644
--- a/cli/tests/workers/worker_nested_error.ts.out
+++ b/cli/tests/workers/worker_nested_error.ts.out
@@ -2,4 +2,4 @@
     at foo ([WILDCARD])
     at [WILDCARD]
 error: Uncaught (in promise) Error: Unhandled error event reached main worker.
-    at Worker.#poll ([WILDCARD])
+    at Worker.#pollControl ([WILDCARD])
diff --git a/extensions/web/lib.rs b/extensions/web/lib.rs
index d74bb619d..6e3552476 100644
--- a/extensions/web/lib.rs
+++ b/extensions/web/lib.rs
@@ -2,7 +2,9 @@
 
 mod message_port;
 
+pub use crate::message_port::create_entangled_message_port;
 pub use crate::message_port::JsMessageData;
+pub use crate::message_port::MessagePort;
 
 use deno_core::error::bad_resource_id;
 use deno_core::error::null_opbuf;
diff --git a/extensions/web/message_port.rs b/extensions/web/message_port.rs
index d10b455d5..f73d0486a 100644
--- a/extensions/web/message_port.rs
+++ b/extensions/web/message_port.rs
@@ -23,7 +23,7 @@ type MessagePortMessage = (Vec<u8>, Vec<Transferable>);
 
 pub struct MessagePort {
   rx: RefCell<UnboundedReceiver<MessagePortMessage>>,
-  tx: UnboundedSender<MessagePortMessage>,
+  tx: RefCell<Option<UnboundedSender<MessagePortMessage>>>,
 }
 
 impl MessagePort {
@@ -37,7 +37,9 @@ impl MessagePort {
 
     // Swallow the failed to send error. It means the channel was disentangled,
     // but not cleaned up.
-    self.tx.send((data.data.to_vec(), transferables)).ok();
+    if let Some(tx) = &*self.tx.borrow() {
+      tx.send((data.data.to_vec(), transferables)).ok();
+    }
 
     Ok(())
   }
@@ -60,6 +62,13 @@ impl MessagePort {
     }
     Ok(None)
   }
+
+  /// This forcefully disconnects the message port from its paired port. This
+  /// will wake up the `.recv` on the paired port, which will return `Ok(None)`.
+  pub fn disentangle(&self) {
+    let mut tx = self.tx.borrow_mut();
+    tx.take();
+  }
 }
 
 pub fn create_entangled_message_port() -> (MessagePort, MessagePort) {
@@ -68,12 +77,12 @@ pub fn create_entangled_message_port() -> (MessagePort, MessagePort) {
 
   let port1 = MessagePort {
     rx: RefCell::new(port1_rx),
-    tx: port1_tx,
+    tx: RefCell::new(Some(port1_tx)),
   };
 
   let port2 = MessagePort {
     rx: RefCell::new(port2_rx),
-    tx: port2_tx,
+    tx: RefCell::new(Some(port2_tx)),
   };
 
   (port1, port2)
@@ -204,5 +213,5 @@ pub async fn op_message_port_recv_message(
     }
   };
   let cancel = RcRef::map(resource.clone(), |r| &r.cancel);
-  resource.port.recv(state.clone()).or_cancel(cancel).await?
+  resource.port.recv(state).or_cancel(cancel).await?
 }
diff --git a/runtime/js/11_workers.js b/runtime/js/11_workers.js
index c917a2880..7267bec38 100644
--- a/runtime/js/11_workers.js
+++ b/runtime/js/11_workers.js
@@ -3,10 +3,13 @@
 
 ((window) => {
   const core = window.Deno.core;
+  const webidl = window.__bootstrap.webidl;
   const { Window } = window.__bootstrap.globalInterfaces;
   const { getLocationHref } = window.__bootstrap.location;
   const { log, pathFromURL } = window.__bootstrap.util;
   const { defineEventHandler } = window.__bootstrap.webUtil;
+  const { deserializeJsMessageData, serializeJsMessageData } =
+    window.__bootstrap.messagePort;
 
   function createWorker(
     specifier,
@@ -34,8 +37,12 @@
     core.opSync("op_host_post_message", id, data);
   }
 
-  function hostGetMessage(id) {
-    return core.opAsync("op_host_get_message", id);
+  function hostRecvCtrl(id) {
+    return core.opAsync("op_host_recv_ctrl", id);
+  }
+
+  function hostRecvMessage(id) {
+    return core.opAsync("op_host_recv_message", id);
   }
 
   /**
@@ -187,18 +194,9 @@
         options?.name,
       );
       this.#id = id;
-      this.#poll();
-    }
-
-    #handleMessage(data) {
-      const msgEvent = new MessageEvent("message", {
-        cancelable: false,
-        data,
-      });
-
-      this.dispatchEvent(msgEvent);
+      this.#pollControl();
+      this.#pollMessages();
     }
-
     #handleError(e) {
       const event = new ErrorEvent("error", {
         cancelable: true,
@@ -219,9 +217,9 @@
       return handled;
     }
 
-    #poll = async () => {
+    #pollControl = async () => {
       while (!this.#terminated) {
-        const [type, data] = await hostGetMessage(this.#id);
+        const [type, data] = await hostRecvCtrl(this.#id);
 
         // If terminate was called then we ignore all messages
         if (this.#terminated) {
@@ -229,11 +227,6 @@
         }
 
         switch (type) {
-          case 0: { // Message
-            const msg = core.deserialize(data);
-            this.#handleMessage(msg);
-            break;
-          }
           case 1: { // TerminalError
             this.#terminated = true;
           } /* falls through */
@@ -262,19 +255,57 @@
       }
     };
 
-    postMessage(message, transferOrOptions) {
-      if (transferOrOptions) {
-        throw new Error(
-          "Not yet implemented: `transfer` and `options` are not supported.",
-        );
+    #pollMessages = async () => {
+      while (!this.terminated) {
+        const data = await hostRecvMessage(this.#id);
+        if (data === null) break;
+        let message, transfer;
+        try {
+          const v = deserializeJsMessageData(data);
+          message = v[0];
+          transfer = v[1];
+        } catch (err) {
+          const event = new MessageEvent("messageerror", {
+            cancelable: false,
+            data: err,
+          });
+          this.dispatchEvent(event);
+          return;
+        }
+        const event = new MessageEvent("message", {
+          cancelable: false,
+          data: message,
+          ports: transfer,
+        });
+        this.dispatchEvent(event);
       }
+    };
 
-      if (this.#terminated) {
-        return;
+    postMessage(message, transferOrOptions = {}) {
+      const prefix = "Failed to execute 'postMessage' on 'MessagePort'";
+      webidl.requiredArguments(arguments.length, 1, { prefix });
+      message = webidl.converters.any(message);
+      let options;
+      if (
+        webidl.type(transferOrOptions) === "Object" &&
+        transferOrOptions !== undefined &&
+        transferOrOptions[Symbol.iterator] !== undefined
+      ) {
+        const transfer = webidl.converters["sequence<object>"](
+          transferOrOptions,
+          { prefix, context: "Argument 2" },
+        );
+        options = { transfer };
+      } else {
+        options = webidl.converters.PostMessageOptions(transferOrOptions, {
+          prefix,
+          context: "Argument 2",
+        });
       }
-
-      const bufferMsg = core.serialize(message);
-      hostPostMessage(this.#id, bufferMsg);
+      const { transfer } = options;
+      const data = serializeJsMessageData(message, transfer);
+      if (this.#terminated) return;
+      hostPostMessage(this.#id, data);
     }
 
     terminate() {
diff --git a/runtime/js/99_main.js b/runtime/js/99_main.js
index 91a4dcefd..d0e86bce7 100644
--- a/runtime/js/99_main.js
+++ b/runtime/js/99_main.js
@@ -42,6 +42,8 @@ delete Object.prototype.__proto__;
   const errors = window.__bootstrap.errors.errors;
   const webidl = window.__bootstrap.webidl;
   const { defineEventHandler } = window.__bootstrap.webUtil;
+  const { deserializeJsMessageData, serializeJsMessageData } =
+    window.__bootstrap.messagePort;
 
   let windowIsClosing = false;
 
@@ -77,9 +79,31 @@ delete Object.prototype.__proto__;
   const onmessage = () => {};
   const onerror = () => {};
 
-  function postMessage(data) {
-    const dataIntArray = core.serialize(data);
-    core.opSync("op_worker_post_message", null, dataIntArray);
+  function postMessage(message, transferOrOptions = {}) {
+    const prefix =
+      "Failed to execute 'postMessage' on 'DedicatedWorkerGlobalScope'";
+    webidl.requiredArguments(arguments.length, 1, { prefix });
+    message = webidl.converters.any(message);
+    let options;
+    if (
+      webidl.type(transferOrOptions) === "Object" &&
+      transferOrOptions !== undefined &&
+      transferOrOptions[Symbol.iterator] !== undefined
+    ) {
+      const transfer = webidl.converters["sequence<object>"](
+        transferOrOptions,
+        { prefix, context: "Argument 2" },
+      );
+      options = { transfer };
+    } else {
+      options = webidl.converters.PostMessageOptions(transferOrOptions, {
+        prefix,
+        context: "Argument 2",
+      });
+    }
+    const { transfer } = options;
+    const data = serializeJsMessageData(message, transfer);
+    core.opSync("op_worker_post_message", data);
   }
 
   let isClosing = false;
@@ -90,12 +114,16 @@ delete Object.prototype.__proto__;
       globalDispatchEvent = globalThis.dispatchEvent.bind(globalThis);
     }
     while (!isClosing) {
-      const bufferMsg = await core.opAsync("op_worker_get_message");
-      const data = core.deserialize(bufferMsg);
+      const data = await core.opAsync("op_worker_recv_message");
+      if (data === null) break;
+      const v = deserializeJsMessageData(data);
+      const message = v[0];
+      const transfer = v[1];
 
       const msgEvent = new MessageEvent("message", {
         cancelable: false,
-        data,
+        data: message,
+        ports: transfer,
       });
 
       try {
diff --git a/runtime/ops/web_worker.rs b/runtime/ops/web_worker.rs
index 39aa2c0a9..026e38157 100644
--- a/runtime/ops/web_worker.rs
+++ b/runtime/ops/web_worker.rs
@@ -1,15 +1,15 @@
 // Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
 
 use crate::web_worker::WebWorkerInternalHandle;
-use crate::web_worker::WorkerEvent;
+use crate::web_worker::WorkerControlEvent;
 use deno_core::error::generic_error;
-use deno_core::error::null_opbuf;
 use deno_core::error::AnyError;
 use deno_core::op_async;
 use deno_core::op_sync;
+use deno_core::CancelFuture;
 use deno_core::Extension;
 use deno_core::OpState;
-use deno_core::ZeroCopyBuf;
+use deno_web::JsMessageData;
 use std::cell::RefCell;
 use std::rc::Rc;
 
@@ -17,7 +17,7 @@ pub fn init() -> Extension {
   Extension::builder()
     .ops(vec![
       ("op_worker_post_message", op_sync(op_worker_post_message)),
-      ("op_worker_get_message", op_async(op_worker_get_message)),
+      ("op_worker_recv_message", op_async(op_worker_recv_message)),
       // Notify host that guest worker closes.
       ("op_worker_close", op_sync(op_worker_close)),
       // Notify host that guest worker has unhandled error.
@@ -31,30 +31,28 @@ pub fn init() -> Extension {
 
 fn op_worker_post_message(
   state: &mut OpState,
+  data: JsMessageData,
   _: (),
-  buf: Option<ZeroCopyBuf>,
 ) -> Result<(), AnyError> {
-  let buf = buf.ok_or_else(null_opbuf)?;
   let handle = state.borrow::<WebWorkerInternalHandle>().clone();
-  handle
-    .post_event(WorkerEvent::Message(buf))
-    .expect("Failed to post message to host");
+  handle.port.send(state, data)?;
   Ok(())
 }
 
-async fn op_worker_get_message(
+async fn op_worker_recv_message(
   state: Rc<RefCell<OpState>>,
   _: (),
   _: (),
-) -> Result<ZeroCopyBuf, AnyError> {
-  let temp = {
-    let a = state.borrow();
-    a.borrow::<WebWorkerInternalHandle>().clone()
+) -> Result<Option<JsMessageData>, AnyError> {
+  let handle = {
+    let state = state.borrow();
+    state.borrow::<WebWorkerInternalHandle>().clone()
   };
-
-  let maybe_data = temp.get_message().await;
-
-  Ok(maybe_data.unwrap_or_else(ZeroCopyBuf::empty))
+  handle
+    .port
+    .recv(state.clone())
+    .or_cancel(handle.cancel)
+    .await?
 }
 
 fn op_worker_close(state: &mut OpState, _: (), _: ()) -> Result<(), AnyError> {
@@ -77,7 +75,7 @@ fn op_worker_unhandled_error(
 ) -> Result<(), AnyError> {
   let sender = state.borrow::<WebWorkerInternalHandle>().clone();
   sender
-    .post_event(WorkerEvent::Error(generic_error(message)))
+    .post_event(WorkerControlEvent::Error(generic_error(message)))
     .expect("Failed to propagate error event to parent worker");
   Ok(())
 }
diff --git a/runtime/ops/worker_host.rs b/runtime/ops/worker_host.rs
index 57d3ac2b8..162f9f4f7 100644
--- a/runtime/ops/worker_host.rs
+++ b/runtime/ops/worker_host.rs
@@ -12,25 +12,23 @@ use crate::permissions::UnaryPermission;
 use crate::permissions::UnitPermission;
 use crate::permissions::WriteDescriptor;
 use crate::web_worker::run_web_worker;
+use crate::web_worker::SendableWebWorkerHandle;
 use crate::web_worker::WebWorker;
 use crate::web_worker::WebWorkerHandle;
-use crate::web_worker::WorkerEvent;
+use crate::web_worker::WorkerControlEvent;
 use crate::web_worker::WorkerId;
 use deno_core::error::custom_error;
-use deno_core::error::null_opbuf;
 use deno_core::error::AnyError;
-use deno_core::error::JsError;
 use deno_core::op_async;
 use deno_core::op_sync;
 use deno_core::serde::de;
 use deno_core::serde::de::SeqAccess;
 use deno_core::serde::Deserialize;
 use deno_core::serde::Deserializer;
-use deno_core::serde_json::json;
 use deno_core::Extension;
 use deno_core::ModuleSpecifier;
 use deno_core::OpState;
-use deno_core::ZeroCopyBuf;
+use deno_web::JsMessageData;
 use log::debug;
 use std::cell::RefCell;
 use std::collections::HashMap;
@@ -51,8 +49,9 @@ pub struct CreateWebWorkerArgs {
   pub use_deno_namespace: bool,
 }
 
-pub type CreateWebWorkerCb =
-  dyn Fn(CreateWebWorkerArgs) -> WebWorker + Sync + Send;
+pub type CreateWebWorkerCb = dyn Fn(CreateWebWorkerArgs) -> (WebWorker, SendableWebWorkerHandle)
+  + Sync
+  + Send;
 
 /// A holder for callback that is used to create a new
 /// WebWorker. It's a struct instead of a type alias
@@ -87,7 +86,8 @@ pub fn init(create_web_worker_cb: Arc<CreateWebWorkerCb>) -> Extension {
         op_sync(op_host_terminate_worker),
       ),
       ("op_host_post_message", op_sync(op_host_post_message)),
-      ("op_host_get_message", op_async(op_host_get_message)),
+      ("op_host_recv_ctrl", op_async(op_host_recv_ctrl)),
+      ("op_host_recv_message", op_async(op_host_recv_message)),
     ])
     .build()
 }
@@ -458,8 +458,9 @@ fn op_create_worker(
   let module_specifier = deno_core::resolve_url(&specifier)?;
   let worker_name = args_name.unwrap_or_else(|| "".to_string());
 
-  let (handle_sender, handle_receiver) =
-    std::sync::mpsc::sync_channel::<Result<WebWorkerHandle, AnyError>>(1);
+  let (handle_sender, handle_receiver) = std::sync::mpsc::sync_channel::<
+    Result<SendableWebWorkerHandle, AnyError>,
+  >(1);
 
   // Setup new thread
   let thread_builder =
@@ -472,17 +473,18 @@ fn op_create_worker(
     //  all action done upon it should be noops
     // - newly spawned thread exits
 
-    let worker = (create_module_loader.0)(CreateWebWorkerArgs {
-      name: worker_name,
-      worker_id,
-      parent_permissions,
-      permissions: worker_permissions,
-      main_module: module_specifier.clone(),
-      use_deno_namespace,
-    });
+    let (worker, external_handle) =
+      (create_module_loader.0)(CreateWebWorkerArgs {
+        name: worker_name,
+        worker_id,
+        parent_permissions,
+        permissions: worker_permissions,
+        main_module: module_specifier.clone(),
+        use_deno_namespace,
+      });
 
     // Send thread safe handle from newly created worker to host thread
-    handle_sender.send(Ok(worker.thread_safe_handle())).unwrap();
+    handle_sender.send(Ok(external_handle)).unwrap();
     drop(handle_sender);
 
     // At this point the only method of communication with host
@@ -497,7 +499,7 @@ fn op_create_worker(
 
   let worker_thread = WorkerThread {
     join_handle,
-    worker_handle,
+    worker_handle: worker_handle.into(),
   };
 
   // At this point all interactions with worker happen using thread
@@ -514,7 +516,7 @@ fn op_host_terminate_worker(
   id: WorkerId,
   _: (),
 ) -> Result<(), AnyError> {
-  let mut worker_thread = state
+  let worker_thread = state
     .borrow_mut::<WorkersTable>()
     .remove(&id)
     .expect("No worker handle found");
@@ -527,52 +529,13 @@ fn op_host_terminate_worker(
   Ok(())
 }
 
-use deno_core::serde::Serialize;
-use deno_core::serde::Serializer;
-
-impl Serialize for WorkerEvent {
-  fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-  where
-    S: Serializer,
-  {
-    let type_id = match &self {
-      WorkerEvent::Message(_) => 0_i32,
-      WorkerEvent::TerminalError(_) => 1_i32,
-      WorkerEvent::Error(_) => 2_i32,
-      WorkerEvent::Close => 3_i32,
-    };
-
-    match self {
-      WorkerEvent::Message(buf) => {
-        Serialize::serialize(&(type_id, buf), serializer)
-      }
-      WorkerEvent::TerminalError(error) | WorkerEvent::Error(error) => {
-        let value = match error.downcast_ref::<JsError>() {
-          Some(js_error) => json!({
-            "message": js_error.message,
-            "fileName": js_error.script_resource_name,
-            "lineNumber": js_error.line_number,
-            "columnNumber": js_error.start_column,
-          }),
-          None => json!({
-            "message": error.to_string(),
-          }),
-        };
-
-        Serialize::serialize(&(type_id, value), serializer)
-      }
-      _ => Serialize::serialize(&(type_id, ()), serializer),
-    }
-  }
-}
-
 /// Try to remove worker from workers table - NOTE: `Worker.terminate()`
 /// might have been called already meaning that we won't find worker in
 /// table - in that case ignore.
 fn try_remove_and_close(state: Rc<RefCell<OpState>>, id: WorkerId) {
   let mut s = state.borrow_mut();
   let workers = s.borrow_mut::<WorkersTable>();
-  if let Some(mut worker_thread) = workers.remove(&id) {
+  if let Some(worker_thread) = workers.remove(&id) {
     worker_thread.worker_handle.terminate();
     worker_thread
       .join_handle
@@ -582,28 +545,28 @@ fn try_remove_and_close(state: Rc<RefCell<OpState>>, id: WorkerId) {
   }
 }
 
-/// Get message from guest worker as host
-async fn op_host_get_message(
+/// Get control event from guest worker as host
+async fn op_host_recv_ctrl(
   state: Rc<RefCell<OpState>>,
   id: WorkerId,
   _: (),
-) -> Result<WorkerEvent, AnyError> {
+) -> Result<WorkerControlEvent, AnyError> {
   let worker_handle = {
-    let s = state.borrow();
-    let workers_table = s.borrow::<WorkersTable>();
+    let state = state.borrow();
+    let workers_table = state.borrow::<WorkersTable>();
     let maybe_handle = workers_table.get(&id);
     if let Some(handle) = maybe_handle {
       handle.worker_handle.clone()
     } else {
       // If handle was not found it means worker has already shutdown
-      return Ok(WorkerEvent::Close);
+      return Ok(WorkerControlEvent::Close);
     }
   };
 
-  let maybe_event = worker_handle.get_event().await?;
+  let maybe_event = worker_handle.get_control_event().await?;
   if let Some(event) = maybe_event {
     // Terminal error means that worker should be removed from worker table.
-    if let WorkerEvent::TerminalError(_) = &event {
+    if let WorkerControlEvent::TerminalError(_) = &event {
       try_remove_and_close(state, id);
     }
     return Ok(event);
@@ -611,22 +574,42 @@ async fn op_host_get_message(
 
   // If there was no event from worker it means it has already been closed.
   try_remove_and_close(state, id);
-  Ok(WorkerEvent::Close)
+  Ok(WorkerControlEvent::Close)
+}
+
+async fn op_host_recv_message(
+  state: Rc<RefCell<OpState>>,
+  id: WorkerId,
+  _: (),
+) -> Result<Option<JsMessageData>, AnyError> {
+  let worker_handle = {
+    let s = state.borrow();
+    let workers_table = s.borrow::<WorkersTable>();
+    let maybe_handle = workers_table.get(&id);
+    if let Some(handle) = maybe_handle {
+      handle.worker_handle.clone()
+    } else {
+      // If handle was not found it means worker has already shutdown
+      return Ok(None);
+    }
+  };
+  worker_handle.port.recv(state).await
 }
 
 /// Post message to guest worker as host
 fn op_host_post_message(
   state: &mut OpState,
   id: WorkerId,
-  data: Option<ZeroCopyBuf>,
+  data: JsMessageData,
 ) -> Result<(), AnyError> {
-  let msg = data.ok_or_else(null_opbuf)?;
-
   debug!("post message to worker {}", id);
-  let worker_thread = state
-    .borrow::<WorkersTable>()
-    .get(&id)
-    .expect("No worker handle found");
-  worker_thread.worker_handle.post_message(msg)?;
+  let worker_handle = {
+    let worker_thread = state
+      .borrow::<WorkersTable>()
+      .get(&id)
+      .expect("No worker handle found");
+    worker_thread.worker_handle.clone()
+  };
+  worker_handle.port.send(state, data)?;
   Ok(())
 }
diff --git a/runtime/web_worker.rs b/runtime/web_worker.rs
index 753238052..a3a062221 100644
--- a/runtime/web_worker.rs
+++ b/runtime/web_worker.rs
@@ -8,6 +8,7 @@ use crate::permissions::Permissions;
 use crate::tokio_util::create_basic_runtime;
 use deno_broadcast_channel::InMemoryBroadcastChannel;
 use deno_core::error::AnyError;
+use deno_core::error::JsError;
 use deno_core::futures::channel::mpsc;
 use deno_core::futures::future::poll_fn;
 use deno_core::futures::future::FutureExt;
@@ -18,6 +19,7 @@ use deno_core::serde::Serialize;
 use deno_core::serde_json;
 use deno_core::serde_json::json;
 use deno_core::v8;
+use deno_core::CancelHandle;
 use deno_core::Extension;
 use deno_core::GetErrorClassFn;
 use deno_core::JsErrorCreateFn;
@@ -26,8 +28,9 @@ use deno_core::ModuleId;
 use deno_core::ModuleLoader;
 use deno_core::ModuleSpecifier;
 use deno_core::RuntimeOptions;
-use deno_core::ZeroCopyBuf;
+use deno_web::create_entangled_message_port;
 use deno_web::BlobUrlStore;
+use deno_web::MessagePort;
 use log::debug;
 use std::cell::RefCell;
 use std::env;
@@ -38,7 +41,6 @@ use std::sync::atomic::Ordering;
 use std::sync::Arc;
 use std::task::Context;
 use std::task::Poll;
-use tokio::sync::Mutex as AsyncMutex;
 
 #[derive(
   Debug, Default, Copy, Clone, PartialEq, Eq, Hash, Serialize, Deserialize,
@@ -55,29 +57,62 @@ impl WorkerId {
   }
 }
 
-type WorkerMessage = ZeroCopyBuf;
-
 /// Events that are sent to host from child
 /// worker.
-pub enum WorkerEvent {
-  Message(WorkerMessage),
+pub enum WorkerControlEvent {
   Error(AnyError),
   TerminalError(AnyError),
   Close,
 }
 
+use deno_core::serde::Serializer;
+
+impl Serialize for WorkerControlEvent {
+  fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+  where
+    S: Serializer,
+  {
+    let type_id = match &self {
+      WorkerControlEvent::TerminalError(_) => 1_i32,
+      WorkerControlEvent::Error(_) => 2_i32,
+      WorkerControlEvent::Close => 3_i32,
+    };
+
+    match self {
+      WorkerControlEvent::TerminalError(error)
+      | WorkerControlEvent::Error(error) => {
+        let value = match error.downcast_ref::<JsError>() {
+          Some(js_error) => json!({
+            "message": js_error.message,
+            "fileName": js_error.script_resource_name,
+            "lineNumber": js_error.line_number,
+            "columnNumber": js_error.start_column,
+          }),
+          None => json!({
+            "message": error.to_string(),
+          }),
+        };
+
+        Serialize::serialize(&(type_id, value), serializer)
+      }
+      _ => Serialize::serialize(&(type_id, ()), serializer),
+    }
+  }
+}
+
 // Channels used for communication with worker's parent
 #[derive(Clone)]
 pub struct WebWorkerInternalHandle {
-  sender: mpsc::Sender<WorkerEvent>,
-  receiver: Rc<RefCell<mpsc::Receiver<WorkerMessage>>>,
+  sender: mpsc::Sender<WorkerControlEvent>,
+  pub port: Rc<MessagePort>,
+  pub cancel: Rc<CancelHandle>,
   terminated: Arc<AtomicBool>,
   isolate_handle: v8::IsolateHandle,
 }
 
 impl WebWorkerInternalHandle {
   /// Post WorkerEvent to parent as a worker
-  pub fn post_event(&self, event: WorkerEvent) -> Result<(), AnyError> {
+  pub fn post_event(&self, event: WorkerControlEvent) -> Result<(), AnyError> {
     let mut sender = self.sender.clone();
     // If the channel is closed,
     // the worker must have terminated but the termination message has not yet been received.
@@ -91,13 +126,6 @@ impl WebWorkerInternalHandle {
     Ok(())
   }
 
-  /// Get the WorkerEvent with lock
-  /// Panic if more than one listener tries to get event
-  pub async fn get_message(&self) -> Option<WorkerMessage> {
-    let mut receiver = self.receiver.borrow_mut();
-    receiver.next().await
-  }
-
   /// Check if this worker is terminated or being terminated
   pub fn is_terminated(&self) -> bool {
     self.terminated.load(Ordering::SeqCst)
@@ -106,6 +134,8 @@ impl WebWorkerInternalHandle {
   /// Terminate the worker
   /// This function will set terminated to true, terminate the isolate and close the message channel
   pub fn terminate(&mut self) {
+    self.cancel.cancel();
+
     // This function can be called multiple times by whomever holds
     // the handle. However only a single "termination" should occur so
     // we need a guard here.
@@ -121,40 +151,52 @@ impl WebWorkerInternalHandle {
   }
 }
 
-#[derive(Clone)]
-pub struct WebWorkerHandle {
-  sender: mpsc::Sender<WorkerMessage>,
-  receiver: Arc<AsyncMutex<mpsc::Receiver<WorkerEvent>>>,
+pub struct SendableWebWorkerHandle {
+  port: MessagePort,
+  receiver: mpsc::Receiver<WorkerControlEvent>,
   terminated: Arc<AtomicBool>,
   isolate_handle: v8::IsolateHandle,
 }
 
-impl WebWorkerHandle {
-  /// Post WorkerMessage to worker as a host
-  pub fn post_message(&self, buf: WorkerMessage) -> Result<(), AnyError> {
-    let mut sender = self.sender.clone();
-    // If the channel is closed,
-    // the worker must have terminated but the termination message has not yet been recieved.
-    //
-    // Therefore just treat it as if the worker has terminated and return.
-    if sender.is_closed() {
-      self.terminated.store(true, Ordering::SeqCst);
-      return Ok(());
+impl From<SendableWebWorkerHandle> for WebWorkerHandle {
+  fn from(handle: SendableWebWorkerHandle) -> Self {
+    WebWorkerHandle {
+      receiver: Rc::new(RefCell::new(handle.receiver)),
+      port: Rc::new(handle.port),
+      terminated: handle.terminated,
+      isolate_handle: handle.isolate_handle,
     }
-    sender.try_send(buf)?;
-    Ok(())
   }
+}
+
+/// This is the handle to the web worker that the parent thread uses to
+/// communicate with the worker. It is created from a `SendableWebWorkerHandle`
+/// which is sent to the parent thread from the worker thread where it is
+/// created. The reason for this seperation is that the handle first needs to be
+/// `Send` when transferring between threads, and then must be `Clone` when it
+/// has arrived on the parent thread. It can not be both at once without large
+/// amounts of Arc<Mutex> and other fun stuff.
+#[derive(Clone)]
+pub struct WebWorkerHandle {
+  pub port: Rc<MessagePort>,
+  receiver: Rc<RefCell<mpsc::Receiver<WorkerControlEvent>>>,
+  terminated: Arc<AtomicBool>,
+  isolate_handle: v8::IsolateHandle,
+}
 
+impl WebWorkerHandle {
   /// Get the WorkerEvent with lock
   /// Return error if more than one listener tries to get event
-  pub async fn get_event(&self) -> Result<Option<WorkerEvent>, AnyError> {
-    let mut receiver = self.receiver.try_lock()?;
+  pub async fn get_control_event(
+    &self,
+  ) -> Result<Option<WorkerControlEvent>, AnyError> {
+    let mut receiver = self.receiver.borrow_mut();
     Ok(receiver.next().await)
   }
 
   /// Terminate the worker
   /// This function will set terminated to true, terminate the isolate and close the message channel
-  pub fn terminate(&mut self) {
+  pub fn terminate(self) {
     // This function can be called multiple times by whomever holds
     // the handle. However only a single "termination" should occur so
     // we need a guard here.
@@ -165,26 +207,26 @@ impl WebWorkerHandle {
       self.isolate_handle.terminate_execution();
     }
 
-    // Wake web worker by closing the channel
-    self.sender.close_channel();
+    self.port.disentangle();
   }
 }
 
 fn create_handles(
   isolate_handle: v8::IsolateHandle,
-) -> (WebWorkerInternalHandle, WebWorkerHandle) {
-  let (in_tx, in_rx) = mpsc::channel::<WorkerMessage>(1);
-  let (out_tx, out_rx) = mpsc::channel::<WorkerEvent>(1);
+) -> (WebWorkerInternalHandle, SendableWebWorkerHandle) {
+  let (parent_port, worker_port) = create_entangled_message_port();
+  let (ctrl_tx, ctrl_rx) = mpsc::channel::<WorkerControlEvent>(1);
   let terminated = Arc::new(AtomicBool::new(false));
   let internal_handle = WebWorkerInternalHandle {
-    sender: out_tx,
-    receiver: Rc::new(RefCell::new(in_rx)),
+    sender: ctrl_tx,
+    port: Rc::new(parent_port),
     terminated: terminated.clone(),
     isolate_handle: isolate_handle.clone(),
+    cancel: CancelHandle::new_rc(),
   };
-  let external_handle = WebWorkerHandle {
-    sender: in_tx,
-    receiver: Arc::new(AsyncMutex::new(out_rx)),
+  let external_handle = SendableWebWorkerHandle {
+    receiver: ctrl_rx,
+    port: worker_port,
     terminated,
     isolate_handle,
   };
@@ -200,7 +242,6 @@ pub struct WebWorker {
   pub js_runtime: JsRuntime,
   pub name: String,
   internal_handle: WebWorkerInternalHandle,
-  external_handle: WebWorkerHandle,
   pub use_deno_namespace: bool,
   pub main_module: ModuleSpecifier,
 }
@@ -237,7 +278,7 @@ impl WebWorker {
     main_module: ModuleSpecifier,
     worker_id: WorkerId,
     options: &WebWorkerOptions,
-  ) -> Self {
+  ) -> (Self, SendableWebWorkerHandle) {
     // Permissions: many ops depend on this
     let unstable = options.unstable;
     let perm_ext = Extension::builder()
@@ -333,15 +374,17 @@ impl WebWorker {
       (internal_handle, external_handle)
     };
 
-    Self {
-      id: worker_id,
-      js_runtime,
-      name,
-      internal_handle,
+    (
+      Self {
+        id: worker_id,
+        js_runtime,
+        name,
+        internal_handle,
+        use_deno_namespace: options.use_deno_namespace,
+        main_module,
+      },
       external_handle,
-      use_deno_namespace: options.use_deno_namespace,
-      main_module,
-    }
+    )
   }
 
   pub fn bootstrap(&mut self, options: &WebWorkerOptions) {
@@ -419,11 +462,6 @@ impl WebWorker {
     }
   }
 
-  /// Returns a way to communicate with the Worker from other threads.
-  pub fn thread_safe_handle(&self) -> WebWorkerHandle {
-    self.external_handle.clone()
-  }
-
   pub fn poll_event_loop(
     &mut self,
     cx: &mut Context,
@@ -446,7 +484,7 @@ impl WebWorker {
           print_worker_error(e.to_string(), &self.name);
           let handle = self.internal_handle.clone();
           handle
-            .post_event(WorkerEvent::Error(e))
+            .post_event(WorkerControlEvent::Error(e))
             .expect("Failed to post message to host");
 
           return Poll::Pending;
@@ -513,7 +551,7 @@ pub fn run_web_worker(
   if let Err(e) = result {
     print_worker_error(e.to_string(), &name);
     internal_handle
-      .post_event(WorkerEvent::TerminalError(e))
+      .post_event(WorkerControlEvent::TerminalError(e))
       .expect("Failed to post message to host");
 
     // Failure to execute script is a terminal error, bye, bye.
@@ -524,134 +562,3 @@ pub fn run_web_worker(
   debug!("Worker thread shuts down {}", &name);
   result
 }
-
-#[cfg(test)]
-mod tests {
-  use super::*;
-  use crate::tokio_util;
-
-  fn create_test_web_worker() -> WebWorker {
-    let main_module = deno_core::resolve_url_or_path("./hello.js").unwrap();
-    let module_loader = Rc::new(deno_core::NoopModuleLoader);
-    let create_web_worker_cb = Arc::new(|_| unreachable!());
-
-    let options = WebWorkerOptions {
-      args: vec![],
-      apply_source_maps: false,
-      debug_flag: false,
-      unstable: false,
-      ca_data: None,
-      user_agent: "x".to_string(),
-      seed: None,
-      module_loader,
-      create_web_worker_cb,
-      js_error_create_fn: None,
-      use_deno_namespace: false,
-      maybe_inspector_server: None,
-      runtime_version: "x".to_string(),
-      ts_version: "x".to_string(),
-      no_color: true,
-      get_error_class_fn: None,
-      blob_url_store: BlobUrlStore::default(),
-      broadcast_channel: InMemoryBroadcastChannel::default(),
-    };
-
-    let mut worker = WebWorker::from_options(
-      "TEST".to_string(),
-      Permissions::allow_all(),
-      main_module,
-      WorkerId(1),
-      &options,
-    );
-    worker.bootstrap(&options);
-    worker
-  }
-
-  #[tokio::test]
-  async fn test_worker_messages() {
-    let (handle_sender, handle_receiver) =
-      std::sync::mpsc::sync_channel::<WebWorkerHandle>(1);
-
-    let join_handle = std::thread::spawn(move || {
-      let mut worker = create_test_web_worker();
-      let source = r#"
-          onmessage = function(e) {
-            console.log("msg from main script", e.data);
-            if (e.data == "exit") {
-              return close();
-            } else {
-              console.assert(e.data === "hi");
-            }
-            postMessage([1, 2, 3]);
-            console.log("after postMessage");
-          }
-          "#;
-      worker.execute_script("a", source).unwrap();
-      let handle = worker.thread_safe_handle();
-      handle_sender.send(handle).unwrap();
-      let r = tokio_util::run_basic(worker.run_event_loop(false));
-      assert!(r.is_ok())
-    });
-
-    let mut handle = handle_receiver.recv().unwrap();
-
-    // TODO(Inteon): use Deno.core.serialize() instead of hardcoded encoded value
-    let msg = vec![34, 2, 104, 105].into_boxed_slice(); // "hi" encoded
-    let r = handle.post_message(msg.clone().into());
-    assert!(r.is_ok());
-
-    let maybe_msg = handle.get_event().await.unwrap();
-    assert!(maybe_msg.is_some());
-
-    let r = handle.post_message(msg.clone().into());
-    assert!(r.is_ok());
-
-    let maybe_msg = handle.get_event().await.unwrap();
-    assert!(maybe_msg.is_some());
-    match maybe_msg {
-      Some(WorkerEvent::Message(buf)) => {
-        // TODO(Inteon): use Deno.core.serialize() instead of hardcoded encoded value
-        assert_eq!(*buf, [65, 3, 73, 2, 73, 4, 73, 6, 36, 0, 3]);
-      }
-      _ => unreachable!(),
-    }
-
-    // TODO(Inteon): use Deno.core.serialize() instead of hardcoded encoded value
-    let msg = vec![34, 4, 101, 120, 105, 116].into_boxed_slice(); // "exit" encoded
-    let r = handle.post_message(msg.into());
-    assert!(r.is_ok());
-    let event = handle.get_event().await.unwrap();
-    assert!(event.is_none());
-    handle.sender.close_channel();
-    join_handle.join().expect("Failed to join worker thread");
-  }
-
-  #[tokio::test]
-  async fn removed_from_resource_table_on_close() {
-    let (handle_sender, handle_receiver) =
-      std::sync::mpsc::sync_channel::<WebWorkerHandle>(1);
-
-    let join_handle = std::thread::spawn(move || {
-      let mut worker = create_test_web_worker();
-      worker
-        .execute_script("a", "onmessage = () => { close(); }")
-        .unwrap();
-      let handle = worker.thread_safe_handle();
-      handle_sender.send(handle).unwrap();
-      let r = tokio_util::run_basic(worker.run_event_loop(false));
-      assert!(r.is_ok())
-    });
-
-    let mut handle = handle_receiver.recv().unwrap();
-
-    // TODO(Inteon): use Deno.core.serialize() instead of hardcoded encoded value
-    let msg = vec![34, 2, 104, 105].into_boxed_slice(); // "hi" encoded
-    let r = handle.post_message(msg.clone().into());
-    assert!(r.is_ok());
-    let event = handle.get_event().await.unwrap();
-    assert!(event.is_none());
-    handle.sender.close_channel();
-
-    join_handle.join().expect("Failed to join worker thread");
-  }
-}