From Xojo Documentation
Sends a "NOOP" command to the mail server.
This is simply a command that asks the server to reply. This can be useful to check that the mail server is still responding and also tells the mail server that you are still connected if there has been no activity for a long period of time.
If successful, the ServerAvailable event handler is called.
In this example, a POP3Socket has been added to the window and named socket1.