code: public static ConnectivityStateInfo forNonError(ConnectivityState state) {
      Preconditions.checkArgument(
          state != TRANSIENT_FAILURE,
          "state is TRANSIENT_ERROR. Use forError() instead");
      return new ConnectivityStateInfo(state, Status.OK);
    }
docs: Returns an instance for a state that is not {@code TRANSIENT_FAILURE}.
  
  @throws IllegalArgumentException if {@code state} is {@code TRANSIENT_FAILURE}.