3v4l.org

run code in 300+ PHP versions simultaneously
<?php ob_end_clean(); header("Connection: close"); ignore_user_abort(); // optional ob_start(); echo ('Text the user will see'); $size = ob_get_length(); header("Content-Length: $size"); ob_end_flush(); // Strange behaviour, will not work flush();            // Unless both are called ! // Do processing here sleep(30);echo('Text user will never see');?>

preferences:
31.55 ms | 402 KiB | 5 Q