Function clone_with_opt_in 

pub fn clone_with_opt_in(
    target: Entity,
    config: impl FnOnce(&mut EntityClonerBuilder<'_, OptIn>) + Send + Sync + 'static,
) -> impl EntityCommand

An EntityCommand that clones parts of an entity onto another entity, configured through EntityClonerBuilder.

This builder tries to clone every component that was explicitly allowed from the source entity, for example by using the allow method.

Required components are also cloned when the target entity does not contain them.