docs: public byte[] serialize( final MemcachedBackupSession session, final byte[] attributesData ) {
          final byte[] sessionData = serializeSessionFields( session );
          final byte[] result = new byte[ sessionData.length + attributesData.length ];
          System.arraycopy( sessionData, 0, result, 0, sessionData.length );
          System.arraycopy( attributesData, 0, result, sessionData.length, attributesData.length );
          return result;
      }