src/vs/base/common/event.ts/Emitter/constructor
class Emitter:	constructor(options?: EmitterOptions) {
		this._options = options;
		this._leakageMon = _globalLeakWarningThreshold > 0 ? new LeakageMonitor(this._options && this._options.leakWarningThreshold) : undefined;
		this._perfMon = this._options?._profName ? new EventProfiling(this._options._profName) : undefined;
	}