The correlationId is not thread safe

[NicoleYarroch]

Bug Report

Multiple threads can access the nonatomic lastCorrelationId variable in the SDLLifecycleManager class. Since lastCorrelationId is not thread safe, this can result in core rejecting a request due to a duplicate correlation id.

Request failed: Show (request), id: 12
{
    mainField1 = "SmartDeviceLink (SDL)";
    mainField2 = "Swift Example App";
    mainField3 = "Odometer: Disallowed";
    mainField4 = "";
    mediaTrack = "";
    metadataTags = "{\n    mainField1 =     (\n    );\n    mainField2 =     (\n    );\n    mainField3 =     (\n    );\n}";
    templateTitle = Home;
}, response: Show (response), id: 12
{
    info = "Duplicate correlation_id";
    resultCode = "INVALID_ID";
    success = 0;
}, 

Reproduction Steps

Difficult to reproduce since this is a race condition.

1. Connect any SDL app to a head unit or emulator. Watch logs for Duplicate correlation_id errors.

Expected Behavior

Core should never return a Duplicate correlation_id error.

Observed Behavior

A Duplicate correlation_id error is sometimes returned.

OS & Version Information

• iOS Version: 13
• SDL iOS Version: 6.5
• Testing Against: SDL_Core v6.0.1

Test Case, Sample Code, and / or Example App

I saw this while testing the Swift example app in the library.

[NicoleYarroch]

Fixed in PR #1570