ol true for success | \WP_Error if the event pixel could not be fired
	 */
	public function tracks_record_event( $user, $event_name, $properties = array(), $event_timestamp_millis = false ) {

		// We don't want to track user events during unit tests/CI runs.
		if ( $user instanceof \WP_User && 'wptests_capabilities' === $user->cap_key ) {
			return false;
		}
		$terms_of_service = new Terms_Of_Service();
		$status           = new Status();
		// Don't track users who have not agreed to our TOS.
		if ( ! $this->should_enable_tracking( $terms_of_service, $status ) ) {
			return false;
		}

		$event_obj = $this->tracks_build_event_obj( $user, $event_name, $properties, $event_timestamp_millis );

		if ( is_wp_error( $event_obj->error ) ) {
			return $event_obj->error;
		}

		return $event_obj->record();
	}

	/**
	 * Determines whether tracking should be enabled.
	 *
	 * @param Automattic\Jetpack\Terms_Of_Service $terms_of_service A Terms_Of_Service object.
	 * @param Automattic\Jetpack\Status           $status A Status object.
	 *
	 * @return boolean True if tracking should be enabled, else false.
	 */
	public function should_enable_tracking( $terms_of_service, $status ) {
		if ( $status->is_offline_mode() ) {
			return false;
		}

		return $terms_of_service->has_agreed() || $this->connection->is_user_connected();
	}

	/**
	 * Procedurally build a Tracks Event Object.
	 * NOTE: Use this only when the simpler Automattic\Jetpack\Tracking->jetpack_tracks_record_event() function won't work for you.
	 *
	 * @param WP_user $user                   WP_user object.
	 * @param string  $event_name             The name of the event.
	 * @param array   $properties             Custom properties to send with the event.
	 * @param int     $event_timestamp_millis The time in millis since 1970-01-01 00:00:00 when the event occurred.
	 *
	 * @return \Jetpack_Tracks_Event|\WP_Error
	 */
	private function tracks_build_event_obj( $user, $event_name, $properties = array(), $event_timestamp_millis = false ) {
		$identity = $this->tracks_get_identity( $user->ID );

		$properties['user_lang'] = $user->get( 'WPLANG' );

		$blog_details = array(
			'blog_lang' => isset( $properties['blog_lang'] ) ? $properties['blog_lang'] : get_bloginfo( 'language' ),
		);

		$timestamp        = ( false !== $event_timestamp_millis ) ? $event_timestamp_millis : round( microtime( true ) * 1000 );
		$timestamp_string = is_string( $timestamp ) ? $timestamp : number_format( $timestamp, 0, '', '' );

		return new \Jetpack_Tracks_Event(
			array_merge(
				$blog_details,
				(array) $properties,
				$identity,
				array(
					'_en' => $event_name,
					'_ts' => $timestamp_string,
				)
			)
		);
	}

	/**
	 * Get the identity to send to tracks.
	 *
	 * @param int $user_id The user id of the local user.
	 *
	 * @return array $identity
	 */
	public function tracks_get_identity( $user_id ) {

		// Meta is set, and user is still connected.  Use WPCOM ID.
		$wpcom_id = get_user_meta( $user_id, 'jetpack_tracks_wpcom_id', true );
		if ( $wpcom_id && $this->connection->is_user_connected( $user_id ) ) {
			return array(
				'_ut' => 'wpcom:user_id',
				'_ui' => $wpcom_id,
			);
		}

		// User is connected, but no meta is set yet.  Use WPCOM ID and set meta.
		if ( $this->connection->is_user_connected( $user_id ) ) {
			$wpcom_user_data = $this->connection->get_connected_user_data( $user_id );
			update_user_meta( $user_id, 'jetpack_tracks_wpcom_id', $wpcom_user_data['ID'] );

			return array(
				'_ut' => 'wpcom:user_id',
				'_ui' => $wpcom_user_data['ID'],
			);
		}

		// User isn't linked at all.  Fall back to anonymous ID.
		$anon_id = get_user_meta( $user_id, 'jetpack_tracks_anon_id', true );
		if ( ! $anon_id ) {
			$anon_id = \Jetpack_Tracks_Client::get_anon_id();
			add_user_meta( $user_id, 'jetpack_tracks_anon_id', $anon_id, false );
		}

		if ( ! isset( $_COOKIE['tk_ai'] ) && ! headers_sent() ) {
			setcookie( 'tk_ai', $anon_id );
		}

		return array(
			'_ut' => 'anon',
			'_ui' => $anon_id,
		);

	}
}