Description:
------------
IMAP extension does not handle 150+ simultaneous transactions.  Random connections to IMAP are dropped.

Run the code below in multiple processes simultaneously to see connections dropped.  

This performance issue is seen in enterprise webmail systems.  Unless caching is used, which it always should, connections will be dropped.

Reproduce code:
---------------
$b =0;
for( $a = 0; $a< 100; $a++)
{
$mbox = imap_open("{localhost:143/imap/notls/novalidate-cert}INBOX", "user", "pass");
if(!$mbox)
        echo "failed ".$b++."\n";
}