Currently, the resharding cloner logic has a potential flaw that could lead to data loss if an exception occurs during the refresh phase. That was spotted after the introduction (and subsequent reversion) of SERVER-92530. While the immediate risk has been mitigated by reverting SERVER-92530, the underlying issue in the cloner logic still needs to be addressed to improve its resilience and prevent potential data loss in future scenarios.

Issue Summary:

• The cloner fetches the list of documents from the donor and writes them to a temporary collection.
• The write operation is managed by resharding::data_copy::withOneStaleConfigRetry, which forces a refresh and re-calls the failed callback in case of a StaleConfig error.
• In such cases, _writeOnceWithNaturalOrder is executed twice.
• However, the dispatchResult query gets moved at the first attempt, resulting in an empty batch on the second attempt.
• This can lead to an empty temporary collection, and as consequence to a data loss.

Currently, the _writeOnceWithNaturalOrder is protected from hitting a StaleConfig as the cloner thread created by the function itself follows the same logic . In case of StaleConfig, it's the cloner thread that refreshes. 
SERVER-92530 introduced the possibility for a refresh to fail. In case of failure, _writeOnceWithNaturalOrder would find stale metadata and behave as described above. Even though reverted, we are still planning to re-commit SERVER-92530 once the related issues are fixed.