src/vs/workbench/services/userData/common/fileUserDataProvider.ts/FileUserDataProvider/watch
class FileUserDataProvider:	watch(resource: URI, opts: IWatchOptions): IDisposable {
		this.watchResources.set(resource, resource);
		const disposable = this.fileSystemProvider.watch(this.toFileSystemResource(resource), opts);
		return toDisposable(() => {
			this.watchResources.delete(resource);
			disposable.dispose();
		});
	}