Service graceful shutdown behavior spike.

[mantzas]

Is your feature request related to a problem? Please describe

When the service is asked to gracefully shutdown we need to make sure that everything and finally the service exits without returning an error (assuming that the shutdown itself does not produce one). Let's investigate if that is the case.

Keep in mind that the service might already work as expected. This is a spike.

Describe the solution

• Make sure that service behaves as expected
• Make sure that tests verify it
• Make any changes in the examples to reflect this behavior