Update startup to explicitly construct a func

[cartermp]

No casting needed!

[halter73]

Thanks for fixing this! I tried out these changes and it appears we're losing the info from the original method when explicitly constructing the Func. In the C# version where we cast, Delegate.Method contains the same MethodInfo you'd get from Type.GetMethod or similar.

Is this something that could be fixed?

Here's the exact error I saw. It's looking for an attribute like HttpGet which won't be necessary after dotnet/aspnetcore#30448, but parameter names and attributes are still important.

Unhandled exception. System.InvalidOperationException: Action must have a pattern. Is it missing a Route attribute?
   at Microsoft.AspNetCore.Builder.MapActionEndpointRouteBuilderExtensions.MapAction(IEndpointRouteBuilder endpoints, Delegate action)
   at <StartupCode$HoudiniPlaygroundFSharp>[email protected](IEndpointRouteBuilder endpoints) in C:\dev\halter73\HoudiniPlaygroundFSharp\Startup.fs:line 34
   ...

[cartermp]

Is this something that could be fixed?

I think it's a bug in F#, yeah. But I can't assess what the priority is at this point.