Using TaskExecutor::sleepFor() has the downside that if there's a primary failover, then a whole new minimumOperationDuration period must elapse before the ReshardingTxnCloners begin again. It would be more efficient to write down the Date_t of when the ReshardingTxnCloners can begin as part of the transition to RecipientStateEnum::kCreatingCollection and use sleepUtil() instead. The Date_t can be calculated from calling TaskExecutor::now() + RecipientStateMachine::_minimumOperationDuration.

for (const auto& txnCloner : _txnCloners) {
    txnClonerFutures.emplace_back(
        executor->sleepFor(minimumOperationDuration, cancelToken)
            .then([executor, cleanupExecutor, cancelToken, txnCloner = txnCloner.get()] {
                return txnCloner->run(executor, cleanupExecutor, cancelToken);
            })
            .share());
}

https://github.com/mongodb/mongo/blob/ead95fd4d389d1e370798cfd9ba098ac27dafd2c/src/mongo/db/s/resharding/resharding_data_replication.cpp#L442

Work on this ticket will also involve

1. Adding a new, optional field to the ReshardingRecipientDocument IDL struct of {type: date, optional: true}.
2. Adding a new, boost::optional<Date_t> _startConfigTxnCloneAt member to RecipientStateMachine and initializing it as ReshardingRecipientDocument::getStartConfigTxnCloneAt() in the constructor and assigning it the value calculated from TaskExecutor::now() + RecipientStateMachine::_minimumOperationDuration following the transition to RecipientStateEnum::kCreatingCollection.