code: func (enc *ICalEncode) WriteLine(s string) {
  	if len(s) <= LineSize {
  		io.WriteString(enc.w, s)
  		return
  	}
  
  	// The first line does not begin with a space.
  	firstLine := truncateString(s, LineSize-len(CRLF))
  	io.WriteString(enc.w, firstLine+CRLF)
  
  	// Reserve three bytes for space + CRLF.
  	lines := splitLength(s[len(firstLine):], LineSize-len(CRLFSP))
  	for i, line := range lines {
  		if i < len(lines)-1 {
  			io.WriteString(enc.w, " "+line+CRLF)
  		} else {
  			// This is the last line, don't append CRLF.
  			io.WriteString(enc.w, " "+line)
  		}
  	}
  }
docs: // WriteLine in ics format max length = LineSize
  // continuation lines start with a space.