I don't know that .net is necessarily not tuned for that use-case. Generally, a generational garbage collector like .net's handles short-lived immutable object

I don't know that .net is necessarily not tuned for that use-case. Generally, a generational garbage collector like .net's handles short-lived immutable objects better than it does longer-lived mutable objects. It can allocate and deallocate objects very quickly as long as they're collected in the first generation. I'm speaking mostly in generalities though. I'd be curious to know if this isn't the case on .net.