code: func writeDate(wr *bufio.Writer, t time.Time) {
  	//store in utc
  	utc := t.In(time.UTC)
  
  	year, month, day := utc.Date()
  
  	wr.WriteUint16(uint16(year) | 0x8000)
  	wr.WriteInt8(int8(month) - 1)
  	wr.WriteInt8(int8(day))
  }
docs: // year: set most sig bit
  // month 0 based