code: func (e *Encoder) Parser(r *http.Request) Parser {
  	contentType := r.Header.Get("Content-Type")
  	info := parseMimeInfo(contentType)
  
  	if info != nil {
  		for encoding, i := range e.encodings {
  			if i.equals(info) {
  				return encoding
  			}
  		}
  	}
  
  	return e.defaultEncoding
  }
docs: // Parser returns a parser based on the mime, if none can be matched the
  // default is returned