code: private FullBinaryMemcacheRequest errorMapRequest() {
          LOGGER.debug("Requesting error map in version {}", MAP_VERSION);
          ByteBuf content = Unpooled.buffer(2).writeShort(MAP_VERSION);
          FullBinaryMemcacheRequest request = new DefaultFullBinaryMemcacheRequest(
              new byte[] {}, Unpooled.EMPTY_BUFFER, content
          );
          request.setOpcode(GET_ERROR_MAP_CMD);
          request.setTotalBodyLength(content.readableBytes());
          return request;
      }
docs: Creates the request to load the error map.