code: @NonNull
      private String determineEncoding(HttpRequest request) {
          MediaType mimeType = request.getContentType();
          if (mimeType == null) return Charsets.UTF_8.name();
          Charset charset = mimeType.getCharset();
          return charset == null ? Charsets.UTF_8.name() : charset.name();
      }
docs: Determine the encoding for the given request.
  
  <p>The default implementation checks the request encoding, falling back to the default encoding specified for
  this resolver.
  
  @param request current request
  
  @return the encoding for the request .