code: @PluginFactory
    public static RollbarAppender createAppender(
        @PluginAttribute("accessToken") @Required final String accessToken,
        @PluginAttribute("endpoint") final String endpoint,
        @PluginAttribute("environment") final String environment,
        @PluginAttribute("language") final String language,
        @PluginAttribute("configProviderClassName") final String configProviderClassName,
        @PluginAttribute("name") @Required final String name,
        @PluginElement("Layout") Layout<? extends Serializable> layout,
        @PluginElement("Filter") Filter filter,
        @PluginAttribute("ignoreExceptions") final String ignore
    ) {
  
      ConfigProvider configProvider = ConfigProviderHelper
          .getConfigProvider(configProviderClassName);
      Config config;
  
      ConfigBuilder configBuilder = withAccessToken(accessToken)
          .environment(environment)
          .endpoint(endpoint)
          .server(new ServerProvider())
          .language(language);
  
      if (configProvider != null) {
        config = configProvider.provide(configBuilder);
      } else {
        config = configBuilder.build();
      }
  
      Rollbar rollbar = new Rollbar(config);
  
      boolean ignoreExceptions = Booleans.parseBoolean(ignore, true);
  
      return new RollbarAppender(name, filter, layout, ignoreExceptions, rollbar);
    }
docs: Create appender plugin factory method.
  
  @param accessToken the Rollbar access token.
  @param endpoint the Rollbar endpoint to be used.
  @param environment the environment.
  @param language the language.
  @param configProviderClassName The class name of the config provider implementation to get
  the configuration.
  @param name the name.
  @param layout the layout.
  @param filter the filter.
  @param ignore the ignore exceptions flag.
  @return the rollbar appender.