How to simulate AutoMapper that works during the build time

Almost two years ago I created the very first version of MappingGenerator. Since then, I’ve put a lot of work in this project, adding new functions and improving the mapping generation algorithm with 14 releases (43 issues/feature requests closed) in the meantime. With over 5.5k downloads from the marketplace and 380 stars on Github, it looks like there is quite a market demand for this kind of tool (even though my coffee button statistics indicate something different).