Sets the parent_refcount field of gstreamer.CapsFeatures This field is used to
determine whether a caps features is mutable or not. This function should only be
called by code implementing parent objects of gstreamer.CapsFeatures, as described in
the MT Refcounting section of the design documents.
Sets the parent_refcount field of gstreamer.CapsFeatures This field is used to determine whether a caps features is mutable or not. This function should only be called by code implementing parent objects of gstreamer.CapsFeatures, as described in the MT Refcounting section of the design documents.