mio has nothing to do with callbacks in its design, unless you build such an abstraction yourself on top of it. However, without an ergonomic way to create sta

mio has nothing to do with callbacks in its design, unless you build such an abstraction yourself on top of it. However, without an ergonomic way to create state machines (i.e. generators), it's hard to use at all in the intended fashion (small per-connection state instead of large boxed closures or coroutine/thread stacks).