code: private void post(final String endpoint, final HttpContent body, final Class responseClass, final KickflipCallback cb) {
          acquireAccessToken(new OAuthCallback() {
              @Override
              public void onSuccess(HttpRequestFactory requestFactory) {
                  request(requestFactory, METHOD.POST, makeApiUrl(endpoint), body, responseClass, cb);
              }
  
              @Override
              public void onFailure(Exception e) {
                  postExceptionToCallback(cb, UNKNOWN_ERROR_CODE);
              }
          });
      }
docs: Do a POST Request, creating a new user if necessary
  
  @param endpoint      Kickflip endpoint. e.g /user/new
  @param body          POST body
  @param responseClass Class of the expected response
  @param cb            Callback that will receive an instance of responseClass