workers: basic event loop (#3828)

* establish basic event loop for workers
* make "self.close()" inside worker
* remove "runWorkerMessageLoop() - instead manually call global function 
  in Rust when message arrives. This is done in preparation for structured clone
* refactor "WorkerChannel" and use distinct structs for internal 
  and external channels;  "WorkerChannelsInternal" and "WorkerHandle"
* move "State.worker_channels_internal" to "Worker.internal_channels"
* add "WorkerEvent" enum for child->host communication; 
  currently "Message(Buf)" and  "Error(ErrBox)" variants are supported
* add tests for nested workers
* add tests for worker throwing error on startup

1 files changed, 1 insertions, 0 deletions

diff --git a/cli/js/unit_tests.ts b/cli/js/unit_tests.ts
index 992169e55..a6435d183 100644
--- a/cli/js/unit_tests.ts
+++ b/cli/js/unit_tests.ts
@@ -59,6 +59,7 @@ import "./write_file_test.ts";
 import "./performance_test.ts";
 import "./permissions_test.ts";
 import "./version_test.ts";
+import "./workers_test.ts";
 
 import { runIfMain } from "../../std/testing/mod.ts";