code: public RESTResponse sendRequest(HttpMethod method, String uri) throws IOException {
          Map<String, String> headers = new HashMap<>();
          return sendRequest(method, uri, headers, null);
      }
docs: Send a REST command with the given method and URI (but no entityt) to the
  server and return the response in a {@link RESTResponse} object.
  
  @param method        HTTP method such as "GET" or "POST".
  @param uri           URI such as "/foo/bar?baz"
  @return              {@link RESTResponse} containing response from server.
  @throws IOException  If an I/O error occurs on the socket.