src/vs/workbench/services/dialogs/browser/fileDialogService.ts/FileDialogService/pickFileToSave
class FileDialogService:	async pickFileToSave(defaultUri: URI, availableFileSystems?: string[]): Promise<URI | undefined> {
		const schema = this.getFileSystemSchema({ defaultUri, availableFileSystems });

		if (this.shouldUseSimplified(schema)) {
			return this.pickFileToSaveSimplified(schema, this.getPickFileToSaveDialogOptions(defaultUri, availableFileSystems));
		}

		const handle = await window.showSaveFilePicker();
		const uuid = generateUuid();
		const uri = URI.from({ scheme: Schemas.file, path: `/${uuid}/${handle.name}` });

		this.fileSystemProvider.registerFileHandle(uuid, handle);

		return uri;
	}