src/vs/workbench/services/search/worker/localFileSearch.ts/LocalFileSearchSimpleWorker/registerCancellationToken
class LocalFileSearchSimpleWorker:	private registerCancellationToken(queryId: number): CancellationTokenSource {
		const source = new CancellationTokenSource();
		this.cancellationTokens.set(queryId, source);
		return source;
	}