The use case is that if we parser the message ,if we received as string frame to JsonNode,and  we may encounter an runtime exception if we are using the play.libs.json.and this will cause the current actor stop.
So if don't provide the way to specified custom supervisor strategy,we must forward message to keep it safe.
cause the handler actor are provide by the user ,so I think that the user will know how to handle the exception of the onReceive code block too.