OpenIdConnectHandler to support async state data format operations

[weijuncitrix]

Is there an existing issue for this?

• I have searched the existing issues

Is your feature request related to a problem? Please describe the problem.

Currently the OpenIdConnectHandler class uses Options.StateDataFormat to protect/unprotect OAuth state, and the interface ISecureDataFormat<TData> does not define any async methods, so the data protection operation here is always synchronous.
This creates a problem for the following use case:
Putting the entire state in state query param could make the URL too large, a common solution to this is putting the actual state in storage and only set an encrypted key in state param which can be used later to retrieve the state.
Obviously the storage operations will need to be async, but the way that OpenIdConnectHandler handles this today, like I mentioned earlier, makes it impossible to do state data protection synchronously. The only option we have is to implement ISecureDataFormat<TData>, call async storage methods and wait for Task results synchronously. But this sort of "sync over async" behavior should best be avoided if possible.

Describe the solution you'd like

One possible solution:

1. define a new interface IAsyncSecureDataFormat<TData>, similar to ISecureDataFormat<TData> except the methods are all async
2. add a new property in OpenIdConnectOptions: IAsyncSecureDataFormat<AuthenticationProperties> AsyncStateDataFormat { get; set; }
3. in OpenIdConnectHandler, use the Options.AsyncStateDataFormat if defined, otherwise fallback to Options.StateDataFormat

Additional context

No response