src/vs/base/common/async.ts/TaskSequentializer/donePending
class TaskSequentializer:	private donePending(taskId: number): void {
		if (this._pending && taskId === this._pending.taskId) {

			// only set pending to done if the promise finished that is associated with that taskId
			this._pending = undefined;

			// schedule the next task now that we are free if we have any
			this.triggerNext();
		}
	}