Register impl_type as an extension which implements extension_type.
Since libpeas 1.22, exten_type can be an Abstract GType and not just an Interface GType
The GType of the extension you implement.
The GType of your implementation of exten_type.
Register impl_type as an extension which implements extension_type.
Since libpeas 1.22, exten_type can be an Abstract GType and not just an Interface GType