Function timeout_cb

c/src/proactor/win_iocp.cpp:2585–2594

runs on a threadpool thread. Must not hold timer_lock.

// runs on a threadpool thread.  Must not hold timer_lock.
VOID CALLBACK timeout_cb(PVOID arg, BOOLEAN /* ignored*/ ) {
  pn_proactor_t *p = (pn_proactor_t *) arg;
  csguard gtimer(&p->timer_lock);
  csguard g(&p->context.cslock);
  if (p->timeout_set)
    p->need_timeout = true;  // else cancelled
  p->timeout_set = false;
  if (p->need_timeout)
    proactor_wake(p);
}

void pn_proactor_set_timeout(pn_proactor_t *p, pn_millis_t t) {
  bool ticking = false;