code: func (b *ByteBuf) WriteUInt32(v uint32) (n int, err error) {
  	b.Expansion(4)
  	Uint32ToBytesTo(v, b.buf[b.writerIndex:b.writerIndex+4])
  	b.writerIndex += 4
  	return 4, nil
  }
docs: // WriteUInt32 write uint32 value to buf using big order
  // return write bytes count, error