code: func (z *Forward) Msgsize() (s int) {
  	s = 1 + msgp.StringPrefixSize + len(z.Tag) + msgp.ArrayHeaderSize
  	for za0001 := range z.Entries {
  		s += 1 + msgp.Int64Size + msgp.GuessSize(z.Entries[za0001].Record)
  	}
  	s += msgp.MapHeaderSize
  	if z.Option != nil {
  		for za0002, za0003 := range z.Option {
  			_ = za0003
  			s += msgp.StringPrefixSize + len(za0002) + msgp.StringPrefixSize + len(za0003)
  		}
  	}
  	return
  }
docs: // Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message