code: void notifyOmemoCarbonCopyReceived(CarbonExtension.Direction direction,
                                         Message carbonCopy,
                                         Message wrappingMessage,
                                         OmemoMessage.Received decryptedCarbonCopy) {
          for (OmemoMessageListener l : omemoMessageListeners) {
              l.onOmemoCarbonCopyReceived(direction, carbonCopy, wrappingMessage, decryptedCarbonCopy);
          }
      }
docs: Notify all registered OmemoMessageListeners of an incoming OMEMO encrypted Carbon Copy.
  Remember: If you want to receive OMEMO encrypted carbon copies, you have to enable carbons using
  {@link CarbonManager#enableCarbons()}.
  
  @param direction             direction of the carbon copy
  @param carbonCopy            carbon copy itself
  @param wrappingMessage       wrapping message
  @param decryptedCarbonCopy   decrypted carbon copy OMEMO element