Askcredential

[pierre-duchene]

Add high level struct for ask credential functionality.
When renew token fail, NetworkStack need to ask caller how to fetch new credentials.

[AliSoftware]

Is it possible to resolve the conflicts first? (You can do a rebase to make the git history clean)

[AliSoftware]

We should do the same for RenewTokenHandler. I see 2 solutions:

• Have a struct for each (generalise the AskCredential struct to give it more generic names, and use an instance of that struct for askCredential and another instance of the same struct for renewToken)
• Have a bigger struct containing the 4 closures and thus grouping informations for both the renewToken and the askCredential at once. This could allow sharing the same triggerCondition for both easily, by providing a convenience constructor taking one triggerCondition and using it for both, for example.

[AliSoftware]

You should be able to just return AskCredential.shouldAskCredential(forError:) I think (the closure and the function have the same signature)

So in fact you can merge those two private funcs into one

[AliSoftware]

Don't forget to add an issue so we think about implementing #21 (review) later