Fix race condition in handleKeepAlive

[saidrhs]

Fix race condition in handleKeepAlive

Description

The code for handleKeepAlive() (which is invoked as part of MQTT_ProcessLoop()) does not invoke the STATE_UPDATE_HOOK macros, but still reads from pContext->lastPacketTxTime. Therefore, this causes a RW race condition which is picked up by ThreadAnalyzer. With a sufficiently meddlesome scheduler, the value of lastPacketTxTime could be different for each time it is checked inside of handleKeepAlive() , causing unreliable behavior in the transmission of KeepAlive packets.

Test Steps

Checklist:

• I have tested my changes. No regression in existing tests.
• I have modified and/or added unit-tests to cover the code changes in this Pull Request.

Related Issue

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[AniruddhaKanhere]

Approved with a Nit pick about the PR description: You have said as seen from above report but I do not see any report in the description attached to the PR.