Added near the beginning of main:

      //   Catapults-specific:
      //     register # open files with sched
      pth_schedvar_register("noof", &cow_noof);
      pth_schedvar_register("idlehands", &numidlehands);

Added in the routine that spawns the thread pool:

      //   Register our per-thread information with the scheduler
      pth_threadvar_register("isresponding", OFFSETOF(thrresponse, isresponding));
      pth_threadvar_register("bytesleft", OFFSETOF(thrresponse, bytesleft));
      ...
      // Create the Catapults scheduler data
      scheddata = malloc(sizeof(thrresponse));
      if (scheddata == NULL) {
        perror("Failed to allocate sched data");
        exit(errno);
      }
      scheddata->isresponding = 0;
      scheddata->bytesleft = 0;
      pth_set_userdata(tid, scheddata);