code: func (d *decoder) nextSpecialChar(p []byte) (i int) {
  	for i = 0; i < len(p); i++ {
  		if p[i] == byte('=') || (d.enc.isText && p[i] == byte('\r')) {
  			return i
  		}
  	}
  	return i
  }
docs: // Return first character position where the character has to be decoded