Tests if session has at a feature of type feature_type (which can be the type of either a ifaceSessionFeature, or else a subtype of some class managed by another feature, such as classAuth).
the #GType of the class of features to check for
true or false
Tests if session has at a feature of type feature_type (which can be the type of either a ifaceSessionFeature, or else a subtype of some class managed by another feature, such as classAuth).