Proposed changes

c8y/devicecontrol/notifications topic, as many others, can contain in its smartrest payload multiple records. For now ensure that multiple records are parsed from this topic in particular, as C8y sends multiple operations in a single message if e.g. device is offline, multiple operations are started, and then the device connects, it then receives all those operations in a single MQTT message.

But a longer term solution would be to refactor the code to ensure that we're supporting collecting multiple smartrest messages from all the possible MQTT topics.

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Improvement (general improvements like code refactoring that doesn't explicitly fix a bug or add any new functionality)
• Documentation Update (if none of the other choices apply)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Paste Link to the issue

#3297

Checklist

• I have read the CONTRIBUTING doc
• I have signed the CLA (in all commits with git commit -s)
• I ran cargo fmt as mentioned in CODING_GUIDELINES
• I used cargo clippy as mentioned in CODING_GUIDELINES
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments