Method push

packages/lib/TaskQueue.js:20–28

(id, callback)

	}

	push(id, callback) {
		if (this.stopping_) throw new Error('Cannot push task when queue is stopping');

		this.waitingTasks_.push({
			id: id,
			callback: callback,
		});
		this.processQueue_();
	}

	processQueue_() {
		if (this.processingQueue_ || this.stopping_) return;