src/vs/workbench/contrib/files/browser/fileImportExport.ts/FileDownload/downloadFileUnbufferedBrowser
class FileDownload:	private async downloadFileUnbufferedBrowser(resource: URI, target: FileSystemWritableFileStream, operation: IDownloadOperation, token: CancellationToken): Promise<void> {
		const contents = await this.fileService.readFile(resource, undefined, token);
		if (!token.isCancellationRequested) {
			target.write(contents.value.buffer);
			this.reportProgress(contents.name, contents.size, contents.value.byteLength, operation);
		}

		target.close();
	}