Due to the way function arguments are treated/overrided in the driver it is
currently impossible to issue the following command:
session.exchange_declare(name, :type => 'fanout')
as the :type variable is shadowed within qpid/datatypes.rb struct method.
A quick workaround is changing the xml spec with a different name (very nasty
though) and everything works (confirming that the attribute is actually honoured).