testUndeliveredMaps_doesNotNotifyIfNothingWasSent() {
    /**
     * @suppress {checkTypes} The callback function type declaration is
     * skipped.
     */
    handler.channelClosed = (channel, opt_pendingMaps, opt_undeliveredMaps) => {
      if (opt_pendingMaps || opt_undeliveredMaps) {
        fail('No pending or undelivered maps should be reported.');
      }
    };

    connect();
    mockClock.tick(ALL_DAY_MS);
    disconnect();
  }
@suppress {checkTypes} The callback function type declaration is
skipped.