Function delete_deleted_phase 

pub async fn delete_deleted_phase<E>(
    conn: &mut dyn IAsyncConnection,
    provider: &dyn IDatabaseProvider,
    db_set: &mut DbSet<E>,
    meta: &EntityTypeMeta,
    query_filter: Option<&BoolExpr>,
) -> EFResult<usize>
where
    E: IEntityType + IEntitySnapshot + IGetKeyValues,

Phase 3: DELETE Deleted entities.