code: static void writeRawVarint32(ByteBuf out, int value) {
          while (true) {
              if ((value & ~0x7F) == 0) {
                  out.writeByte(value);
                  return;
              } else {
                  out.writeByte((value & 0x7F) | 0x80);
                  value >>>= 7;
              }
          }
      }
docs: Writes protobuf varint32 to (@link ByteBuf).
  @param out to be written to
  @param value to be written