src/vs/workbench/contrib/tasks/browser/abstractTaskService.ts/TaskMap/getKey
class TaskMap:	public static getKey(workspaceFolder: IWorkspace | IWorkspaceFolder | string): string {
		let key: string | undefined;
		if (Types.isString(workspaceFolder)) {
			key = workspaceFolder;
		} else {
			const uri: URI | null | undefined = isWorkspaceFolder(workspaceFolder) ? workspaceFolder.uri : workspaceFolder.configuration;
			key = uri ? uri.toString() : '';
		}
		return key;
	}