feature_type is the type of a class that implements
SoupSessionFeature, this creates a new feature of that type and
adds it to
session as with
soup_session_add_feature(). You can use
this when you don’t need to customize the new feature in any way.
Adding multiple features of the same
feature_type is not allowed.
feature_type is not a
SoupSessionFeature type, this gives each
existing feature on
session the chance to accept
a “subfeature”. This can be used to add new
SoupAuth types, for instance.
See the main
SoupSession documentation for information on what
features are present in sessions by default.