Open Source .NET Framework that abstract out AWS CDK calls to EventBridge

Could you clarify what exactly you are looking to do? The existing open source AWS CDK library makes it very easy to create an EventBus in EventBridge that your application code can later use. For example, in one project I use the following to create one:

LicensingEventBus = new EventBus(this, "LicensingEvents", new EventBusProps
    {
        EventBusName = "LicensingEvents"
    }
);

In my application code, I then use the AWS SDK for .NET to push events on to the EventBus:

_ebClient = new AmazonEventBridgeClient();
var transactionEvents = new PutEventsRequest();
var busEntry = new PutEventsRequestEntry
    {
        Source = this.GetType().Namespace,
        EventBusName = _eventBusName,
        DetailType = "transaction",
        Time = DateTime.Now,
        Detail = myEventJson
    };
transactionEvents.Entries.Add(busEntry);
await _ebClient.PutEventsAsync(transactionEvents);