Gets whether the distance is valid or not.
When a function returns a ColliderDistance2D struct, it may not be valid because the Collider2D used as distance references were not valid in some way due to them being disabled or not having any valid shapes. This property indicates whether the other distance properties can be used and are valid or not.
Additional resources: Physics2D.Distance, Collider2D.Distance and Rigidbody2D.Distance.