i want exclude debug infomation when output csv

@InsiteFX  @kenjis
thanks every time.
The cause this time seemed to be that a string was returned upon return.
I stopped returning view and replaced it with exit

PHP Code:

    public function csvExport(): string
    {
          :
        // close stream
        fclose($stream);
        
        // TODO: Debugging information is attached to the output CSV.
        // return view('home/index');
        exit();
    } 


Why can I write to a closed CSV? after fclose command.
Is 'php://output' involved?