worker: make Worker async disposable

Author: jasnell

doc/api/worker_threads.md

@@ -1863,6 +1863,21 @@ Calling `unref()` on a worker allows the thread to exit if this is the only
 active handle in the event system. If the worker is already `unref()`ed calling
 `unref()` again has no effect.
 
+### `worker[Symbol.asyncDispose]()`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+Calls [`worker.terminate()`][] when the dispose scope is exited.
+
+```js
+async function example() {
+  await using worker = new Worker('for (;;) {}', { eval: true });
+  // Worker is automatically terminate when the scope is exited.
+}
+```
+
 ## Notes
 
 ### Synchronous blocking of stdio

lib/internal/worker.js

@@ -19,6 +19,7 @@ const {
   String,
   StringPrototypeTrim,
   Symbol,
+  SymbolAsyncDispose,
   SymbolFor,
   TypedArrayPrototypeFill,
   Uint32Array,
@@ -407,6 +408,10 @@ class Worker extends EventEmitter {
     });
   }
 
+  async [SymbolAsyncDispose]() {
+    await this.terminate();
+  }
+
   ref() {
     if (this[kHandle] === null) return;