public async Task<string> OpenAsync(CancellationToken cancellationToken)
{
await mOptions.PrepareAsync();
var useDefaultConsumerGroup = !string.IsNullOrEmpty(mOptions.EventHubConsumerGroupName);
mMessagingFactory = MessagingFactory.CreateFromConnectionString(mOptions.EventHubConnectionString);
mEventHubClient = mMessagingFactory.CreateEventHubClient(mOptions.EventHubName);
mConsumerGroup = useDefaultConsumerGroup ?
mEventHubClient.GetConsumerGroup(mOptions.EventHubConsumerGroupName)
: mEventHubClient.GetDefaultConsumerGroup();
return string.Concat(mEventHubNamespace, "/",
mOptions.EventHubName, "/",
useDefaultConsumerGroup ? "<default group>" : mOptions.EventHubConsumerGroupName);
}