Cannot receive data from iAP session when app is suspended on iOS11

[t-yoshii]

Bug Report

On iOS11, we observe the issue that iOS does not resume app to “Running” from “Suspended” state even when it received data from EA session.

As a result we hit following 2 issues:
a. Connection to SDL Core fails when app is launched in background.
b. App is not resumed to “AUDIBLE” state after audio interruption.

Reproduction Steps

a. Connection to SDL Core fails when app is launched in background.

1. App launched in background and start connection
2. If certain connection step costs more than about 5 sec, app are transitioned to “Suspended” state by iOS.
3. Core sends data to app, however, iOS does not resume app to “running”.
4. Proxy misses the data and fails to connect to Core

b. App is not resumed to “AUDIBLE” state after temporal audio interruption.

1. SDLApp1 playing audio in background.
2. SDLApp2 plays audio (Audio streaming, TTS, VR etc.) and SDLApp1 become NOT_AUDIBLE. (HU does not support mixing audio)
3. SDLApp1 becomes “Suspended” because it stops audio playing.
4. SDLApp2 stop playing and Core notifies “AUDIBLE” to SDLApp1, however, iOS does not resume SDLApp1 to “running”.
5. SDLApp1 stays in NOT_AUDIBLE

Expected Behavior

a. Connection to SDL Core fails when app is launched in background.
App successfully connects SDL core even when it is launched in background.

b. App is not resumed to “AUDIBLE” state after audio interruption.
App is successfully resumed to AUDIBLE after audio interruption ends.

OS & Version Information

• iOS Version: iOS11
• SDL iOS Version: 4.7.4 and 5.0.0
• Testing Against: Our internal devboard.

Test Case, Sample Code, and / or Example App

I will create PR later.