Sent Packet
                                                   ^     
                                                   |     
                                               +-------+ 
                                               |Send   | 
         .-------------------------------------|State  | 
         |                                     |Machine| 
         |                                     +-------+ 
         |                                         ^     
         |                                         |     
         |                                    Send Queue     
         |                                +-----------------+   
         |                                | | | | | | | | | |    
         |                                +-----------------+
         |                                         ^       
         |                                         |          LANai Memory 
- - - - -|- - - - - - - - - - - - - - - - - - - - -|- - - - - - - - - - - -
         |                                         |   User Process Memory 
         V                                         |                       
Receive Event Queue                                |                       
+-----------------+                      .---------'                       
| | | | | | | | | |                      |                                 
+-----------------+                      |                                 
        |                                |                                 
        |                             .--^--.                                 
        |   gm_send_with_callback(...,ptr,len,callback,context)               
        |   ...                                  |        |                   
        `-> event=gm_receive();                  |        |                
            switch(event.recv.type){             |        |                
              ...                                |        |                
              default:                           |        |                
                gm_unknown(port,event);          |        |                
            }                |     `-------------|--.     |                
                             `--------.          |  |     |                 
                                .-----|----------'  |     |                 
                                |     |     .-------|-----'                    
                                |     |     |       |                          
                         + - - -|- - -|- - -|- - - -|- - - - - - - - - - - +   
                         |      V     V     V       V                      |   
                         |  callback(port,context,status)                  |   
                         |                                                 |   
                         |            [behind the scenes in gm_unknown()]  |   
                         + - - - - - - - - - - - - - - - - - - - - - - - - +