code: private IPPacket handleFragmentation(final IPPacket ipPacket) {
          if (this.fragmentListener == null) {
              return null;
          }
          try {
              return this.fragmentListener.handleFragment(ipPacket);
          } catch (final Throwable t) {
              logger.warn("Exception thrown by FragmentListener when processing the IP frame", t);
          }
          return null;
      }
docs: Helper method to deal with the {@link FragmentListener} since it
  technically can throw exceptions and stuff so we just want to catch all
  and log and move on.
  
  @param ipPacket
  @return