typedef struct CbCProc <Type, Impl> {
  __code sched(Impl* cbc_proc, __code next(...));
  __code sleep(Impl* cbc_proc, void* chan, struct spinlock* lk, __code next(...));
  __code sleep1(Impl* cbc_proc, __code next1(...));
  __code wakeup(Impl* cbc_proc, void* chan, __code next1(...));
  __code wakeup1(Impl* cbc_proc, void* chan, __code next(...));
  __code next(....);
  __code next1(...);
} CbCProc;