title: What does joinOnce do in NEHotspotConfiguration do?
body: <p>I am trying to do autoconnect in iOS with below code</p>
  
  <pre><code>if([Utils isEmpty:password]){
    configuration = [[NEHotspotConfiguration alloc] initWithSSID: wifiSSID];
  }else{
    configuration = [[NEHotspotConfiguration alloc] initWithSSID: wifiSSID passphrase: password isWEP: NO];
  }
  configuration.joinOnce = YES;
  
  /* Alert the OS that the user wants to connect to the WiFi */
  [[NEHotspotConfigurationManager sharedManager] applyConfiguration: configuration completionHandler: ^ (NSError * _Nullable error) {
    if (nil == error) {
      DLog (@ "Is Connected!!");
      [WiFiManager sendCallback:CONNECTED callback:callback];
    } else {
      DLog (@ "Error is:%@", error);
      [WiFiManager sendCallback:UNKNOWN callback:callback];
  }}];
  </code></pre>
  
  <p>Here I have joinOnce = YES.
  What does this actually do when it is set to NO.
  I don't find any real difference between YES and NO.</p>
  
  <p>Anyone please explain.</p>