static <A> bool waitForVarToChange_withTimeout(Var<A> v, A knownValue, long timeout) ctex {
  synchronized(v) {
    long destTime = sysNow()+timeout, remainingTime;
    while ((remainingTime = destTime-sysNow()) > 0) {
      if (neq(knownValue, v!)) true;
      v.wait(remainingTime);
    }
    false;
  }
}