code: @NotNull
      @ObjectiveCName("addEndpoint:")
      public ConfigurationBuilder addEndpoint(@NotNull String url) {
          try {
              endpoints.addEndpoint(url);
          } catch (ConnectionEndpointArray.UnknownSchemeException e) {
              throw new RuntimeException(e.getMessage());
          }
          return this;
      }
docs: Adding Endpoint for API
  Valid URLs are:
  tcp://[host]:[port]
  tls://[host]:[port]
  ws://[host]:[port]
  wss://[host]:[port]
  
  @param url endpoint url
  @return this