feat(ext/fetch): allow `Deno.HttpClient` to be declared with `using` (#21453)

This commit adds a method of `Symbol.dispose` to the object returned
from `Deno.createHttpClient`, so we can make use of [explicit resource
management](https://github.com/tc39/proposal-explicit-resource-management)
by declaring it with `using`.

1 files changed, 27 insertions, 0 deletions

diff --git a/cli/tests/unit/fetch_test.ts b/cli/tests/unit/fetch_test.ts
index d12a93867..b4d248440 100644
--- a/cli/tests/unit/fetch_test.ts
+++ b/cli/tests/unit/fetch_test.ts
@@ -1618,6 +1618,33 @@ Deno.test(
   },
 );
 
+Deno.test(
+  { permissions: { net: true } },
+  async function createHttpClientExplicitResourceManagement() {
+    using client = Deno.createHttpClient({});
+    const response = await fetch("http://localhost:4545/assets/fixture.json", {
+      client,
+    });
+    const json = await response.json();
+    assertEquals(json.name, "deno");
+  },
+);
+
+Deno.test(
+  { permissions: { net: true } },
+  async function createHttpClientExplicitResourceManagementDoubleClose() {
+    using client = Deno.createHttpClient({});
+    const response = await fetch("http://localhost:4545/assets/fixture.json", {
+      client,
+    });
+    const json = await response.json();
+    assertEquals(json.name, "deno");
+    // Close the client even though we declared it with `using` to confirm that
+    // the cleanup done as per `Symbol.dispose` will not throw any errors.
+    client.close();
+  },
+);
+
 Deno.test({ permissions: { read: false } }, async function fetchFilePerm() {
   await assertRejects(async () => {
     await fetch(import.meta.resolve("../testdata/subdir/json_1.json"));