This is the Stack abstraction for the active object that waits
for messages to appear on the wire and processes these messages
by calling the MessageFactory interface to create a ServerRequest
or ServerResponse object. The main job of the message processor is
to instantiate message channels for the given transport.
version: JAIN-SIP-1.1 version: This code is in the public domain.
Creates a message channel for the specified host/port.
Parameters: targetHostPort - destination for logged message New MessageChannel for this processor.