Ask HN: What makes omnisharp so slow?

Anyone who tried omnisharp must have noticed how incredibly slow it is. Things which should be instant takes seconds not even mentioning all other problems it has. Its so slow it made me curious why? Lately I have been interested in software performance and I would like to understand omnisharp architecture and decisions they made because there must be some valuable lessons there obviously it was not written to be slow but ended up to be. For now I have very limited understanding of how it works so maybe there is somebody with better understanding of its architecture who could give me some tips or bits of knowledge.