code: public static HttpResponse fromObject(HttpHeaders headers, @Nullable Object content,
                                            ObjectMapper mapper) {
          return fromObject(headers, content, HttpHeaders.EMPTY_HEADERS, mapper);
      }
docs: Creates a new JSON Text Sequences of the specified {@code content}.
  
  @param headers the HTTP headers supposed to send
  @param content the object supposed to send as contents
  @param mapper the mapper which converts the content object into JSON Text Sequences