mono: encapsulate internal delegates
Summary: Depends on D10337
Test Plan: meson setup -Dbindings=mono,cxx -Dmono-beta=true
Reviewers: segfaultxavi, Jaehyun_Cho, YOhoho, brunobelo
Reviewed By: YOhoho
Subscribers: cedric, reviewers, committers, woohyun
Tags: efl
Differential Revision: https://phab.enlightenment.org/D10339