Callback object for Pre-Interaction type events.
This, like all other callback objects are automatically reused and you should not keep any reference to them.
Arbiter related to callback event.
In the case that this pre-event occurs between two non-Shape's then this is the first arbiter to be created for the related interactionType
First Interactor involved in callback event.
This interactor will have CbType set matched by the first OptionType in InteractionListener
Second Interactor involved in callback event.
This interactor will have CbType set matched by the second OptionType in InteractionListener
Describes how Arbiter's objects are related to int1/int2 properties
If true, then arbiter.shape1 will belong to callback.int2, and arbiter.shape2 will belong to callback.int1.
If you take the arbiter's normal, then if swapped is true, the normal will point from int2 towards int1 instead of from int1 towards int2.