Function add_physics_components 

fn add_physics_components(
    send_now: bool,
    comp_sync_package: &mut CompSyncPackage<EcsCompPacket>,
    uid: Uid,
    pos: Pos,
    last_pos: Option<u32>,
    ori: Option<(&Ori, Option<u32>)>,
    vel: Option<(&Vel, Option<u32>)>,
)

Adds physics components if send_now is true or Option<Last<T>> is None.

If Last<T> isn’t present, this is recorded as an insertion rather than a modification.