Function insert_batch 

pub fn insert_batch<I, B>(batch: I, insert_mode: InsertMode) -> impl Command
where
    I: IntoIterator<Item = (Entity, B)> + Send + Sync + 'static,
    B: Bundle<Effect: NoBundleEffect>,

A Command that consumes an iterator to add a series of Bundles to a set of entities.

If any entities do not exist in the world, this command will return a TryInsertBatchError.

This is more efficient than inserting the bundles individually.