The EnhancedDebugger is a debugger that allows to debug sent, received and interpreted messages
but also provides the ability to send ad-hoc messages composed by the user.
Returns the presence info for a particular user, or null if the user
is unavailable (offline) or if no presence information is available, such as
when you are not subscribed to the user's presence updates.
Returns the presence info for a particular user's resource, or null if the user
is unavailable (offline) or if no presence information is available, such as
when you are not subscribed to the user's presence updates.
Returns an iterator for all the user's current presences or null if the user
is unavailable (offline) or if no presence information is available, such as
when you are not subscribed to the user's presence updates.
Subscription requests are ignored, which means they must be manually
processed by registering a listener for presence packets and then looking
for any presence requests that have the type Presence.Type.SUBSCRIBE.