- (BOOL)startServer {
  for (int i = 0; i < 10; i++) {
    //  随机端口号
    NSInteger port = arc4random_uniform(64510) + 1025;
    NSDictionary *options = @{
      GCDWebServerOption_ConnectedStateCoalescingInterval : @(20),
      GCDWebServerOption_Port : @(port)
    };
    NSError *error = nil;
    if ([self.webServer startWithOptions:options error:&error]) {
      DDLogDebug(@"Start local server: %@", self.webServer.serverURL);
      return YES;
    }
  }
  return NO;
}