Consider using ActivatorUtilities.CreateFactory in AuthenticationHandlerProvider

[pakrym]

ActivatorUtilities.CreateInstance is 30x slower than invoking factory delegate.

/cc @Tratcher @HaoK

[HaoK]

I'm not familiar with the CreateFactory method, how does that behavior compared to CreateInstance, what are the main differences between the two methods?

[HaoK]

Namely we need the authentication handlers to be created per request with (potentially) new instances of their ctor args, so if CreateFactory is faster because its not getting things from DI every time, that won't work...

[pakrym]

It optimizes constructor selection and invocation by generating delegate object ObjectFactory(IServiceProvider serviceProvider, object[] arguments); that you can call repeatedly.
The only thing that is fixed is type being resolved so the delegate has to be cached per requested type.

[HaoK]

So the only time you should use CreateInstance is when its a one time creation, all other times we should prefer CreateFactory?

[pakrym]

Yes, especially if it's anywhere close to "per request"

[HaoK]

Is this something that should be done for preview 2 or is this a pretty safe change we can do as a perf fix in rc?

[analogrelay]

AuthenticationHandlerProvider

Sounds like this is actually area-security. Probably can wait until we see a perf need here.

Never mind, this type is actually in HttpAbstractions in the end ;)