src/vs/workbench/contrib/audioCues/browser/observable.ts/FromEventObservable/handleEvent
class FromEventObservable:	private readonly handleEvent = (args: TArgs | undefined) => {
		const newValue = this.getValue(args);
		if (this.value !== newValue) {
			this.value = newValue;

			if (this.hasValue) {
				transaction(tx => {
					for (const o of this.observers) {
						tx.updateObserver(o, this);
						o.handleChange(this, undefined);
					}
				});
			}
			this.hasValue = true;
		}
	};