src/vs/editor/browser/widget/codeEditorWidget.ts/BooleanEventEmitter/setValue
class BooleanEventEmitter:	public setValue(_value: boolean) {
		const value = (_value ? BooleanEventValue.True : BooleanEventValue.False);
		if (this._value === value) {
			return;
		}
		this._value = value;
		if (this._value === BooleanEventValue.True) {
			this._onDidChangeToTrue.fire();
		} else if (this._value === BooleanEventValue.False) {
			this._onDidChangeToFalse.fire();
		}
	}