* @param datastoreType the {@link Datastore} type that will be accessed
* @param txFunction the {@link InterruptibleCheckedFunction} that needs a new read-write transaction
* @return the {@link FluentFuture} returned by {@link ReadWriteTransaction#commit()}, or a failed future with an
* @param datastoreType the {@link Datastore} type that will be accessed
* @param txFunction the {@link InterruptibleCheckedFunction} that needs a new read-write transaction
* @return the {@link FluentFuture} returned by {@link ReadWriteTransaction#commit()}, or a failed future with an