UCP callback to handle the connection request in a client-server connection establishment flow.
This structure is used for handling an incoming connection request on the listener. Setting this type of handler allows creating an endpoint on any other worker and not limited to the worker on which the listener was created.
Other than communication progress routines, it is allowed to call all other communication routines from the callback in the struct.
The callback is thread safe with respect to the worker it is invoked on.
It is the user’s responsibility to avoid potential dead lock accessing different worker.
Connection request callback
User defined argument for the callback