anchor.diff:              this.RegisterCorrelatedInner comp registration true Gen.id ecs
           | Alloc entityId ->
               this.RegisterCorrelatedInner comp registration false entityId ecs
  -        | Postalloc entityId ->
  +        | PostAlloc entityId ->
               if preDeque.Count > 0 then
                   let preallocId = preDeque.RemoveFromFront ()
                   let index = this.Correlations.[preallocId]
  
positive.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]
  
negative.code: 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
  
  /// A freezable type.
  /// TODO: move to Prime?
  