Added support for external URLSession handling for having things like certificate pinning

[lesmuc]

Description of changes:
Added another init function that allows setting the URL Session from external. This will bring the possibility to implement the URLSessionDelegate outside the AWS Mobile AppSync SDK sources.

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[palpatim]

I agree with the use case, but I think I'd like to do this as part of a larger refactor. This class is a bit of a mess, and adding your initializer to just the "API Key" authentication type leaves a gap, (not to mention that the proposed initializer doesn't include a retryStrategy argument :) ).

I'm working on a larger PR with a new initializer like so:

public init(
    url: URL,
    urlSession: URLSession,
    authProvider: AppSyncAuthProvider,
    sendOperationIdentifiers: Bool,
    retryStrategy: AWSAppSyncRetryStrategy
)

Where AppSyncAuthProvider is an internal enum of AWSAppSyncHTTPNetworkTransport, that matches closely with the existing AWSAppSyncAuthType:

public enum AppSyncAuthProvider {
    case awsIAM(provider: AWSCredentialsProvider, endpoint: AWSEndpoint)
    case apiKey(AWSAPIKeyAuthProvider)
    case oidcToken(AWSOIDCAuthProvider)
    case amazonCognitoUserPools(AWSCognitoUserPoolsAuthProvider)
}

So to solve your use case, you'd do something like:

let session = URLSession(...with my configuration and delegate and queue)
let transport = AWSAppSyncHTTPNetworkTransport(
        url: url,
        urlSession: session,
        authProvider: .apiKey(myAPIKeyProvider),
        sendOperationIdentifiers: true,
        retryStrategy: .exponential
    )

Thoughts?

[lesmuc]

Thoughts?

Sorry for my late response and thanks for your message. Your proposal / PR looks good for me!

[palpatim]

#422 released on https://github.com/awslabs/aws-mobile-appsync-sdk-ios/releases/tag/3.1.11