Sets whether the Collider will be used or not used by a CompositeCollider2D.
When a CompositeCollider2D is used, the Collider geometry is merged together with any other Colliders using the same Composite Collider.
When a Collider is used by a Composite Collider, the Editor will ignore and not show the Collider2D.sharedMaterial, Collider2D.isTrigger & Collider2D.usedByEffector properties. The same properties on the CompositeCollider2D will be used instead. You should set these properties on the Composite Collider instead to merge all colliders into the composite Collider.
This usedByComposite property is only available in BoxCollider2D and PolygonCollider2D.