A strategy for resolving a "user" destination by translating it to one or more
actual destinations one per active user session. When sending a message to a
user destination, the destination must contain the user name so it may be
extracted and used to look up the user sessions. When subscribing to a user
destination, the destination does not have to contain the user's own name.
We simply use the current session.
See implementation classes and the documentation for example destinations.