Transaction timeout limit hints

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I am putting myself in the shoes of someone trying to experiment with a new, more complex transaction. With that in mind, I start a transaction and start shaping my transaction. From a QLDB perspective, I should probably be experimenting outside of a transaction, and then having something ready to go to work within the (current) 30 second limit, but I might be coming from not having to think about this.

As I'm querying, I get an error communication failure: InvalidSessionException: Transaction 05K97LfBBVa60AK0qMbc6R has expired

This could be a little jarring - did I do something wrong? Do I need to update the expiration time? is QLDB not working? etc? I might not realize that it's a hard limit of the service at this point.

If feasible, I would suggest a couple small tweaks to explicitly describe the issue so there's no confusion as to whether it's user error or QLDB error.

Suggestions:

1/ when a transaction is started, print out the transaction time limit. Even better if we could have a countdown like we are thinking for the console query editor.
2/ when the error is received, would it be worth also stating whatever the transaction time limit is?

At the very least, perhaps we should consider updating the error message to say "Transaction ... has expired, please see QLDB limits documentation for more information." This way, it is immediately clear they're bumping against a service limit rather than thinking they're not doing something correctly.

Tangential: we should consider doing similar for session expiration errors as well, if they hit the 13-17 minute session timeout