code: protected Response post(Object payload, Object... pathArgs) throws IOException {
          URL url = getApiUrl(pathArgs);
          Entity<?> entity = Entity.entity(payload, MediaType.APPLICATION_JSON);
          return (invocation(url, null).post(entity));
      }
docs: Perform an HTTP POST call with the specified payload object and URL, returning
  a ClientResponse instance with the data returned from the endpoint.
  
  @param payload the object instance that will be serialized to JSON and used as the POST data
  @param pathArgs variable list of arguments used to build the URI
  @return a ClientResponse instance with the data returned from the endpoint
  @throws IOException if an error occurs while constructing the URL