What is the reason to have non-generic request interfaces?

[ghost]

Its make them similar for notification interfaces.
So, using of non-generic requests can confuse.

If you want response you must use requests, otherwise just notification.

[jbogard]

In the case of a request without a response, in case you don't have one. Notifications target multiple handlers, also.

[ghost]

Why you want to know notification will handle once?

You do not wait for response.
You do not know how it is handling.
You do not know was it handled.

All are good, are not?

[jbogard]

Not quite sure I understand you - both Send and Publish block for handlers to respond.

Sometimes Send doesn't have a response, but since C# doesn't let you use a Void type as a type parameter, I had to create a helper interface.

Send = 1 -> 1
Publish = 1 -> *

Send = Request/Response. Sometimes response is null
Publish = Broadcast. Can't have a response.