csharp: Using Count eina_promises.
Summary: ref T8422
Reviewers: lauromoura, felipealmeida, YOhoho, segfaultxavi
Reviewed By: lauromoura
Subscribers: cedric, reviewers, committers
Tags: efl
Maniphest Tasks: T8422
Differential Revision: https://phab.enlightenment.org/D10498