$wgEventStreams = [
  'test.metrics_platform.interactions' => [
    'schema_title' => '/analytics/product_metrics/web/base',
    'destination_event_service' => 'eventgate-analytics-external',
    'producers' => [
      'metrics_platform_client' => [
        'provide_values' => [
          'performer_is_logged_in',
          'mediawiki_skin',
        ],
      ],
    ],
  ],
];

// When $wgEventLoggingStreamNames is false (not falsy), the EventLogging
// JavaScript client will treat all streams as if they are configured and
// registered.
$wgEventLoggingStreamNames = [ 'test.metrics_platform.interactions' ];

mw.eventLog.submitInteraction('test.metrics_platform.interactions', '/analytics/product_metrics/web/base/1.0.0', 'init');