Function spawn

vm/ByteCodeTranslator/src/javascript/parparvm_runtime.js:2601–2626

(threadObject, generator)

    return null;
  },
  spawn(threadObject, generator) {
    const thread = { id: this.nextThreadId++, object: threadObject, generator: generator, waiting: null, interrupted: false, done: false };
    this.threads.push(thread);
    if (shouldTraceThread(thread)) {
      vmTrace("runtime.spawn.thread-" + thread.id + ":" + threadDebugLabel(threadObject));
    }
    if (VM_DIAG_ENABLED && (thread.id | 0) > 1 && (thread.id | 0) <= 4) {
      vmTrace("runtime.spawn.stack.thread-" + thread.id + ":" + String(new Error().stack || ""));
    }
    // Sync methods (translated to plain ``function`` instead of
    // ``function*``) return non-iterable values — most commonly
    // ``undefined`` for a ``void`` return. ``drain`` calls
    // ``generator.next()`` and would explode on such a value, so
    // short-circuit here: the method already ran to completion when
    // the caller evaluated its arg, so the thread is done the moment
    // it's spawned.
    if (generator == null || typeof generator.next !== "function") {
      thread.done = true;
      if (threadObject) {
        threadObject[CN1_THREAD_ALIVE] = 0;
      }
      return thread;
    }
    this.enqueue(thread);
    return thread;
  },
  flushPendingFireAndForget() {
    if (this.pendingFireAndForget.length === 0) return;
    const batch = this.pendingFireAndForget;