`Show a message'
To show a message, you can use this command:
C: MESSAGE
S: OK
alternativly you may add an option to confirm:
C: CONFIRM --one-button
S: OK
The client should use SETDESC to set an appropriate text before
issuing this command, and may use SETOK to set the text for the
dismiss button. The value returned is OK or an error message.
From the protocol