code: protected function doPostAction($uri, array $data = [])
      {
          $this->setActionUri($uri);
  
          try {
              $response = $this->client->post($this->uri, ['json' => $data]);
          } catch (ClientException $e) {
              $response = $e->getResponse();
          } catch (ServerException $e) {
              $response = $e->getResponse();
          }
  
          return $this->responseToJson($response);
      }
docs: Create or update a resource
  
  @param string $uri
  @param array $data
  @return array