Return a login object that the requested connection should be
Note that the connection is at this time bound to the master object,
and will be re-bound to the returned object.
The lfun logon() will be applied to the login object after
binding the connection to it. That lfun has to return != 0 to
If connect() initiates a secure connection without setting a callback,
and the connection is still handshaking at the time connect() returns,
the driver will delay the call to logon() until the handshake either
succeeds or fails.
LDMud 3.2.13/3.3.713 streamlined the handling of secure connections
logon(A), disconnect(M), interactive(E), exec(E),