Event arguments that represent reachability
상속: System.EventArgs
 private void OnReachabilityUpdated(object sender, ReachabilityEventArgs reachabilityEventArgs)
 {
     Ready = true;
     if (ReachabilityUpdated != null)
     {
         ReachabilityUpdated(this, EventArgs.Empty);
     }
 }
 protected virtual void HandleReachabilityUpdated(object sender, ReachabilityEventArgs e)
 {
     UpdateStatusLabel(e.Status, StatusLabel);
 }