Persist test set sample questions to TestSetGenerator object so as to not lose work

[ahgraber]

Describe the Feature I am currently on a tier 1 account with Anthropic, which means I have a daily cap of 1M tokens (total - in and out). When trying to generate a testset of 100 questions, I hit that daily token limit and the generator.generate call raises a RateLimitError. However, the data is not preserved, which means I have now paid for 1M tokens but critically do not have access to the results.

Therefore, as a developer I would like the generated test questions to be persisted to the TestSetGenerator object as they are received so that I can access the testset up to the point that the Exception occurred. Even better would be to catch the Exception and enter a "pause" state so that the next day I could run something like generator.continue() and pick up where I left off.

Why is the feature important for you? See above

Additional context Add any other context about the feature you want to share with us.