public async Task AppendToStreamAsync <T>(string stream, object metadata, T @event)
 {
     await AppendToStreamAsync(stream, ExpectedVersion.Any, NewEventData.Create(@event, metadata)).ConfigureAwait(false);
 }
 public async Task AppendToStreamAsync <T>(string stream, params T[] events)
 {
     await AppendToStreamAsync(stream, ExpectedVersion.Any, events.Select(x => NewEventData.Create(x)).ToArray()).ConfigureAwait(false);
 }