src/vs/workbench/api/common/extHostSearch.ts/ExtHostSearch/$provideFileSearchResults
class ExtHostSearch:	$provideFileSearchResults(handle: number, session: number, rawQuery: IRawFileQuery, token: vscode.CancellationToken): Promise<ISearchCompleteStats> {
		const query = reviveQuery(rawQuery);
		const provider = this._fileSearchProvider.get(handle);
		if (provider) {
			return this._fileSearchManager.fileSearch(query, provider, batch => {
				this._proxy.$handleFileMatch(handle, session, batch.map(p => p.resource));
			}, token);
		} else {
			throw new Error('unknown provider: ' + handle);
		}
	}