anchor.diff:  open Nito.Collections
   open Prime
   
  +/// The manner in which a component is registered.
   type [<Struct>] Registration =
       | Prealloc
       | Alloc of AllocId : Guid
  -    | Postalloc of PostallocId : Guid
  +    | PostAlloc of PostAllocId : Guid
   
   /// A freezable type.
   /// TODO: move to Prime?
  
positive.code:             this.RegisterCorrelatedInner comp registration true Gen.id ecs
          | Alloc entityId ->
              this.RegisterCorrelatedInner comp registration false entityId ecs
          | Postalloc entityId ->
              if preDeque.Count > 0 then
                  let preallocId = preDeque.RemoveFromFront ()
                  let index = this.Correlations.[preallocId]
  
negative.code:             this.RegisterCorrelatedInner comp true Gen.id
          | Alloc entityId ->
              this.RegisterCorrelatedInner comp false entityId
          | PostAlloc entityId ->
              if preDeque.Count > 0 then
                  let preallocId = preDeque.RemoveFromFront ()
                  let index = correlations.[preallocId]
  