Because of the growing need to offload compute to GPUs and other types of customized hardware, asynchronous programming has become a necessary feature of modern programming languages. In this talk we will share our experience in designing and implementing the asynchronous programming feature in Mojo, an MLIR based language. We will reflect on our poor experience trying to use LLVM’s coroutines and walk through how we mitigated the same deficiencies when rewriting the passes in MLIR.