Which PHP Functions Must Be Called Before Using flush()? A Complete Guide to the Correct Order

Correct Example of Calling Order:

<?php  
ob_start();                // Start output buffering  
echo "First output segment\n";  
ob_flush();                // Flush PHP's output buffer to the server  
flush();                   // Send the content to the browser  
<p>sleep(2);                  // Simulate a time-consuming operation</p>
<p>echo "Second output segment\n";<br>
ob_flush();<br>
flush();</p>
<p>ob_end_flush();            // End buffering and send any remaining content<br>
?><br>

By mastering the correct order of these essential functions, you can maximize the effectiveness of flush(), enabling real-time output and a smoother user experience.