send_reply
Description:
Send a reply to an user message.
If reply is floating, it's consumed. You can only send a reply to a 
      UserMessage that has been received.
Parameters:
| this | |
| reply | 
           a UserMessage to send as reply  | 
      
Send a reply to an user message.
If reply is floating, it's consumed. You can only send a reply to a 
      UserMessage that has been received.
| this | |
| reply | 
           a UserMessage to send as reply  |