PHP session Read and write lock problem

After the Session_Start (), the corresponding session file is locked until the current script is closed to unlock it.
During lockdown, Session_Start () begins when a process accesses a file that has the same session ID to be unlocked.
The solution is to call Session_write_close () to write the data to the file and end the session after it has been set.

For example, the following code

PHP Code
<?php
Session_name ("Stest");
session_id ("TestID");
Session_Start ();
$_session["Count"]=0;
Session_write_close ();
Sleep (10);
echo "Success";
?>

If you do not join Session_write_close ();
Concurrent 3 Processes access the page, the first process executes 10 seconds, the second executes 20 seconds, and the third executes for 30 seconds.
After joining Session_write_close ()
Concurrent 3 processes will be completed in 10 seconds