CL-GSERVER.MESSAGEB
MESSAGE-BOX/BT → MESSAGE-BOX-BASE ... → T
Bordeaux-Threads based message-box with a single thread operating on a message queue. This is used when the gserver is created outside of the `system'. There is a limit on the maximum number of gservers/actors/agents that can be created with this kind of queue because each message-box requires exactly one thread.