augmentTimeoutError = (message, tracker) => {
  if (message.startsWith("Navigation Timeout Exceeded")) {
    const urls = tracker.urls();
    if (urls.length > 1) {
      message += `\nTracked URLs that have not finished: ${urls.join(", ")}`;
    } else if (urls.length > 0) {
      message += `\nFor ${urls[0]}`;
    } else {
      message += `\nBut there are no pending connections`;
    }
  }
  return message;
}
Adds information about timed out URLs if given message is about Timeout.

@param {string} message error message
@param {Object} tracker ConnectionTracker
@returns {string}