@Override
  public String toString() {
    return String.format("The status of listener %s is %s",
        listenerId, status);
  }
A message that is sent to a particular agent who was registered a health listener on a GemFireVM.
This message is only sent when the health status changes.

@since GemFire 3.5
geode-core/src/main/java/org/apache/geode/internal/admin/remote/HealthListenerMessage.java