src/vs/workbench/contrib/files/browser/fileImportExport.ts/BrowserFileUpload/upload
class BrowserFileUpload:	upload(target: ExplorerItem, source: DragEvent | FileList): Promise<void> {
		const cts = new CancellationTokenSource();

		// Indicate progress globally
		const uploadPromise = this.progressService.withProgress(
			{
				location: ProgressLocation.Window,
				delay: 800,
				cancellable: true,
				title: localize('uploadingFiles', "Uploading")
			},
			async progress => this.doUpload(target, this.toTransfer(source), progress, cts.token),
			() => cts.dispose(true)
		);

		// Also indicate progress in the files view
		this.progressService.withProgress({ location: VIEW_ID, delay: 500 }, () => uploadPromise);

		return uploadPromise;
	}