code: public byte[] serializeAttributes( final MemcachedBackupSession session, final ConcurrentMap<String, Object> attributes ) {
          return _attributesTranscoder.serializeAttributes( session, attributes );
      }
docs: Serialize the given session attributes to a byte array, this is delegated
  to {@link SessionAttributesTranscoder#serializeAttributes(MemcachedBackupSession, ConcurrentMap)} (using
  the {@link SessionAttributesTranscoder} provided in the constructor of this class).
  
  @param session the session that owns the given attributes.
  @param attributes the attributes to serialize.
  @return a byte array representing the serialized attributes.
  
  @see de.javakaffee.web.msm.SessionAttributesTranscoder#serializeAttributes(MemcachedBackupSession, ConcurrentMap)