Get all users based on a specific permission/role in .Net CSOM in SharePoint 2013

I want to get the list of all the users who have a particular role/permission on a site. For example, I need the list of users who have edit rights (RoleType=Editor) using .Net CSOM in SharePoint 2013. They can be in any group. I tried many things. However, it seems there isn't a straight forward way to do this. Any ideas?

Thanks in adavance.