Other actions cannot be performed on the web page during PHP download.

During PHP download, the webpage cannot perform other operations. I have a page for download. the code is as follows: Header & nbsp; (& nbsp; 'cache-Control: & nbsp; no-Cache, & nbsp; must-revalidate '& nbsp;); Header & nbsp; (& n other actions cannot be performed on the webpage during PHP download
I have a page to download. the code is as follows:
Header ('cache-Control: no-Cache, must-revalidate ');
Header ('content-type: application/octet-stream ');
Header ('Accept-Ranges: bytes ');
Header ('content-Length: '. $ this-> _ filesizebytes );
Header ('content-Disposition: attachment; filename = "'. $ this-> _ filename .'"');
$ File = fopen ($ this-> _ fileFullPath, "r ");
$ Buffer = fig (1024 );
While (! Feof ($ file )){
Echo fread ($ file, $ buffer );
Flush ();
}
Fclose ($ file );
The problem is that when I perform the download and other actions, the response will be stopped, and then the operation will be executed after the file download is complete. this is the case on the local or remote server, why?
Thank you.
PHP server Buffer shared:
------ Solution --------------------
If the session is not used, it will not happen.