✨ Add timestamp, id and checksum info for a received message

[lsabi]

Add metadata for received message.

I'm not sure if it makes sense to also add:

• MessageState
• Headers
• Length

I think that for now, timestamp and id are the most important, especially if we consider the implementation of the Pollingstrategy with the timestamp (which I'm trying to use). Since checksum is also a primitive data type, I've also added it (why not?)

[mmodzelewski]

I'm not sure if it makes sense to also add:

• MessageState
• Headers
• Length

The end goal would be to have full capabilities of the underlying SDK, so I'd say we should include these eventually.

[lsabi]

@mmodzelewski I've fixed the checksum's return and added also the remaining information, but the headers which I don't know what is a good way of representing them. Maybe a dict? If you have any suggestions, let me know or feel free to edit and then merge the branch.

[mmodzelewski]

I think dict would be good for headers, but it will require more work as it can hold different types of data. We can leave it for another PR.

[lsabi]

@mmodzelewski did you get a chance to look at the PR?

[lsabi]

@mmodzelewski have looked at this PR?

[mmodzelewski]

Hey @lsabi, I added a commit with an enum implementation I mentioned in an earlier comment.