extensions/typescript-language-features/src/tsServer/requestQueue.ts/RequestQueue/enqueue
class RequestQueue:	public enqueue(item: RequestItem): void {
		if (item.queueingType === RequestQueueingType.Normal) {
			let index = this.queue.length - 1;
			while (index >= 0) {
				if (this.queue[index].queueingType !== RequestQueueingType.LowPriority) {
					break;
				}
				--index;
			}
			this.queue.splice(index + 1, 0, item);
		} else {
			// Only normal priority requests can be reordered. All other requests just go to the end.
			this.queue.push(item);
		}
	}