void callAlertListener(Alert alert) {
    if (!isListening()) {
      return;
    }
    if (alertListener != null && alert.getLevel() >= alertLevel) {
      alertListener.alert(alert);
    }
  }
Sends the given {@code alert} to this agent's {@link AlertListener}.
geode-core/src/main/java/org/apache/geode/internal/admin/remote/RemoteGfManagerAgent.java