Some may find writing switch steps manually tedious. If your compiler supports __COUNTER__ (which is pretty likely), you can use "corodef.h" helper macros.
CoroDef(N)codegen macro defines Coro struct with N-sized stack. for example, CoroDef(128) will codegen Coro128 with stack of 128 bytes in size. makes sense to use smaller Coro, when nesting it to parent coro's stack with newcvar(). e.g.