Tip: Pattern matching and sealed message types

[Zetanova]

There is a performance increase to pattern match on sealed message types vs non-sealed message types
Reference: https://devblogs.microsoft.com/dotnet/performance-improvements-in-net-6/#peanut-butter

It is a good practice to seal all used message types and also make them immutable.

[Zetanova]

@Aaronontheweb I don't know there you wrote it that u benchmark the switch statement vs the akka fluent matcher
the .net team maybe improved something in this area in c# 11 see: dotnet/roslyn#5835