extensions/typescript-language-features/src/tsServer/callbackMap.ts/CallbackMap/destroy
class CallbackMap:	public destroy(cause: string): void {
		const cancellation = new ServerResponse.Cancelled(cause);
		for (const callback of this._callbacks.values()) {
			callback.onSuccess(cancellation);
		}
		this._callbacks.clear();
		for (const callback of this._asyncCallbacks.values()) {
			callback.onSuccess(cancellation);
		}
		this._asyncCallbacks.clear();
	}