// used from instances of other classes to tell that they are no longer interested for messages of type audio
public void RemoveMessageHandler(SpawnersMessageHandler messageHandler)
{
spanwnersMessageHandlers.Remove(messageHandler);
}
// used from instances of other classes to tell that they are interested for messages of type audio
public void AddMessageHandler(SpawnersMessageHandler messageHandler)
{
spanwnersMessageHandlers.Add(messageHandler);
}