[NATIVESDK-156] Allow configuration of async request runModes

[vishalduggal]

Changes in APSHTTPClient for NATIVESDK-156

[matt-langston]

@vishalduggal has this been tested with aps_sdk? I think this teasing is blocked by NATIVESDK-150 and NATIVESDK-155. I am the owner of these issues, so the ball is in my court and I will resolve it so that you can test accordingly.

This seems like an excellent improvement, and a clear step in the right direction. Can you provide a few assertions to the code that communications your assumptions (specifically pre and post conditions) and maybe a few XCTest unit tests in the provided unit test target that communicates your theory of operation?

This would help me understand your thinking and design rationale. Don't get me wrong, I definitely like the direction, but I want/need to make sure that my understanding of what you are trying to accomplish matches with your expectations.

[matt-langston]

Great job on this @vishalduggal. The unit tests you provided made your PR easy to test.