src/vs/base/common/worker/simpleWorker.ts/SimpleWorkerProtocol/sendMessage
class SimpleWorkerProtocol:	public sendMessage(method: string, args: any[]): Promise<any> {
		const req = String(++this._lastSentReq);
		return new Promise<any>((resolve, reject) => {
			this._pendingReplies[req] = {
				resolve: resolve,
				reject: reject
			};
			this._send(new RequestMessage(this._workerId, req, method, args));
		});
	}