src/vs/base/common/observableImpl/base.ts/ObservableValue/set
class ObservableValue:	public set(value: T, tx: ITransaction | undefined, change: TChange): void {
		if (this.value === value) {
			return;
		}

		if (!tx) {
			transaction((tx) => {
				this.set(value, tx, change);
			}, () => `Setting ${this.debugName}`);
			return;
		}

		const oldValue = this.value;
		this.value = value;
		getLogger()?.handleObservableChanged(this, { oldValue, newValue: value, change, didChange: true });

		for (const observer of this.observers) {
			tx.updateObserver(observer, this);
			observer.handleChange(this, change);
		}
	}