src/vs/workbench/contrib/mergeEditor/browser/utils.ts/ReentrancyBarrier/makeExclusive
class ReentrancyBarrier:	public makeExclusive<TFunction extends Function>(fn: TFunction): TFunction {
		return ((...args: any[]) => {
			if (this._isActive) {
				return;
			}
			this._isActive = true;
			try {
				return fn(...args);
			} finally {
				this._isActive = false;
			}
		}) as any;
	}