src/vs/workbench/services/search/common/searchService.ts/SearchService/clearCache
class SearchService:	clearCache(cacheKey: string): Promise<void> {
		const clearPs = [
			this.diskSearch,
			...Array.from(this.fileSearchProviders.values())
		].map(provider => provider && provider.clearCache(cacheKey));

		return Promise.all(clearPs)
			.then(() => { });
	}