This talk is for the curious developer who uses coroutines and wants to understand their inner workings. What does it mean to be a lightweight thread? How are suspensions implemented? What is the role of the compiler in the process? We'll talk about continuations, thread management, integration points with Android, and we'll even re-implement common suspendable functions. This will be a deep dive, expect to read code, some of which was not meant for most developers to see.