code: function handleBrowserRegister(log, config, browser) {
    // Create a alias Id for each browser.name. Used in identifying coverage reports
    config.browserIdAlias[browser.name] =
      config.browserIdAlias[browser.name] ||
      Math.floor(Math.random() * Date.now());
    config.nextShardIndex[browser.name] =
      config.nextShardIndex[browser.name] || 0;
    config.shardIndexMap[browser.id] = config.nextShardIndex[browser.name];
    log.debug(
      `registering browser id ${browser.id} with aggregated browser id ${
        config.browserIdAlias[browser.name]
      } at shard index ${config.shardIndexMap[browser.id]}`
    );
    config.nextShardIndex[browser.name]++;
  }
docs: TODO: Browser unregister?? We likely need to reset our shard indexes and browser-id aliases if we restart our browsers or if connections get reset.