docs: public Charset getCharset() {
      // RFC2616 3.7
      for (String type : this.request.headers().getAll("Content-Type")) {
        int idx = type.toUpperCase().indexOf("CHARSET=");
        if (idx > 1) {
          String charset = type.substring(idx+8);
          return Charset.forName(charset);
        }
      }
      return Charset.forName("UTF-8");
    }