Solution when flush ()-based output cannot be in sequence

In linux, first confirm whether to add ob_start () and ob_flush (). Copy codeThe Code is as follows: ob_start ();
For ($ I = 1; $ I <= 10; $ I ++ ){
Echo $ I. "<br/> \ n ";
Ob_flush ();
Flush ();
Usleep (500000 );
}

If the output is still unavailable, add the header information before the code.Copy codeThe Code is as follows: header ("Content-Type: text/html; charset = utf8 ;");
Ob_start ();
For ($ I = 1; $ I <= 10; $ I ++ ){
Echo $ I. "<br/> \ n ";
Ob_flush ();
Flush ();
Usleep (500000 );
}