MediatR Support for dispatching

[praschl]

So implementers don't have to reference the full project.

[praschl]

or even better: do not require an interface at all, to be able to write handlers which do not require any reference to Google.gRPC or MiP.Grpc

When trying to find a handler for Out Say(In parameter), look for a public method which

• Task RunAsync(In, ServiceCallContext)
• Task RunAsync(In)
• Task RunAsync(In, ServiceCallContext)
• Task RunAsync(In)
• Task RunAsync(ServiceCallContext);
• Task RunAsync();
• Task RunAsync(ServiceCallContext);
• Task RunAsync();

maybe also look for methods named "SayAsync"

first method to be found on any type of given assembly will be used.
Name of handled method could still come from

• class name
• attributes on class or method
• parameter when adding a handler manually

[praschl]

Instead of doing that, support https://github.com/jbogard/MediatR.
This is more complicated, but also more flexible (help wanted)