Fix: Execute all messages received from SQS

[LeonieAdis]

📢 Type of change

• Bugfix
• New feature
• Enhancement
• Refactoring

📜 Description

After the SimpleMessageListenerContainer has received SQS messages from a queue it does not check again, that the queue is still running and delivers all messages to their handlers even if the queue has stopped in the meantime.

💡 Motivation and Context

If a SimpleMessageListenerContainer is stopped, e.g. because the service instance is shut down, it might happen that while stopping, the container still receives some SQS messages from a queue, but doesn't distribute those messages to their handlers.
As a result, the SQS messages are invisible for other service instances that are listening to the same queue until the visibility timeout of the messages is reached. This causes a delay of the message delivery.
With this fix, all messages that are pulled from the queue - and thus set invisible - are delivered to their handlers and can therefore be processed, even if the SimpleMessageListenerContainer is stopped or the service is shut down.

💚 How did you test it?

Added a unit test:

• Start a SimpleMessageListenerContainer
• Send a SQS message
• Stop the SimpleMessageListenerContainer
• Verify that the message was received by its handler

📝 Checklist

• I reviewed submitted code
• I added tests to verify changes
• I updated reference documentation to reflect the change
• All tests passing
• No breaking changes

🔮 Next steps

[maciejwalkowiak]

Looks good to me, thanks for submitting PR!

@eddumelendez would you like to take a look?

[birnbuazn]

Any news on this?