code: private static BinaryMemcacheRequest handleTouchRequest(final ChannelHandlerContext ctx, final TouchRequest msg) {
          ByteBuf extras = ctx.alloc().buffer();
          extras.writeInt(msg.expiry());
  
          byte[] key = msg.keyBytes();
          short keyLength = (short) key.length;
          byte extrasLength = (byte) extras.readableBytes();
          BinaryMemcacheRequest request = new DefaultBinaryMemcacheRequest(key);
          request.setExtras(extras);
          request.setOpcode(OP_TOUCH);
          request.setKeyLength(keyLength);
          request.setTotalBodyLength(keyLength + extrasLength);
          request.setExtrasLength(extrasLength);
          return request;
      }
docs: Encodes a {@link TouchRequest} into its lower level representation.
  
  @return a ready {@link BinaryMemcacheRequest}.