The function accepting-handle-user-info
returns the user-info associated with the handle accepting-handle, which is the user-info argument to accept-tcp-connections-creating-async-io-states.
The system does nothing with the user-info, and its purpose is to allow you to pass information to the connection-function of accept-tcp-connections-creating-async-io-states.
LispWorks User Guide and Reference Manual - 20 Sep 2017