fn build_initial_add_mutation(
fragment_infos: &HashMap<FragmentId, InflightFragmentInfo>,
backfill_ordering: &ExtendedFragmentBackfillOrder,
actor_splits: HashMap<ActorId, ConnectorSplits>,
) -> Mutationfn build_initial_add_mutation(
fragment_infos: &HashMap<FragmentId, InflightFragmentInfo>,
backfill_ordering: &ExtendedFragmentBackfillOrder,
actor_splits: HashMap<ActorId, ConnectorSplits>,
) -> Mutation