var log = new StringBuilder();
DeviceWatcher watcher = DeviceInformation.CreateWatcher(DeviceClass.PortableStorageDevice);
watcher.EnumerationCompleted += async (DeviceWatcher obj, object args) =>
{
  log.AppendLine("EnumerationCompleted");
  await Log(log);
};

watcher.Added += async (DeviceWatcher obj, DeviceInformation args) =>
{
  log.AppendLine("Added "+args.Id);
  foreach (var prop in args.Properties)
  {
    log.AppendFormat("    Propertiey Key {0} Value {1} {2}", prop.Key, prop.Value, Environment.NewLine);
  } 
        
  await Log(log);
};

watcher.Removed += async (DeviceWatcher obj, DeviceInformationUpdate args) =>
{
  log.AppendLine("Removed " + args.Id);        
  foreach (var prop in args.Properties)
  {
    log.AppendFormat("    Propertiey Key {0} Value {1} {2}", prop.Key, prop.Value, Environment.NewLine);
  }

  await Log(log);
};

watcher.Start();