code: func runeAt(body []byte, position int) (code rune, charWidth int) {
  	if len(body) <= position {
  		// <EOF>
  		return -1, utf8.RuneError
  	}
  
  	c := body[position]
  	if c < utf8.RuneSelf {
  		return rune(c), 1
  	}
  
  	r, n := utf8.DecodeRune(body[position:])
  	return r, n
  }
docs: // Gets the rune from the byte array at given byte position and it's width in bytes