src/vs/base/common/worker/simpleWorker.ts/SimpleWorkerServer/_handleMessage
class SimpleWorkerServer:	private _handleMessage(method: string, args: any[]): Promise<any> {
		if (method === INITIALIZE) {
			return this.initialize(<number>args[0], <any>args[1], <string>args[2], <string[]>args[3]);
		}

		if (!this._requestHandler || typeof this._requestHandler[method] !== 'function') {
			return Promise.reject(new Error('Missing requestHandler or method: ' + method));
		}

		try {
			return Promise.resolve(this._requestHandler[method].apply(this._requestHandler, args));
		} catch (e) {
			return Promise.reject(e);
		}
	}