src/vs/base/common/worker/simpleWorker.ts/SimpleWorkerProtocol/constructor
class SimpleWorkerProtocol:	constructor(handler: IMessageHandler) {
		this._workerId = -1;
		this._handler = handler;
		this._lastSentReq = 0;
		this._pendingReplies = Object.create(null);
		this._pendingEmitters = new Map<string, Emitter<any>>();
		this._pendingEvents = new Map<string, IDisposable>();
	}