DeltaIOArrowK.scala

            case Put(create) => State(s => {
              // Id and revision for the new data we will create
              val id = Id[A](Guid(s.deltaId.clientId, s.deltaId.clientDeltaId, WithinDeltaId(s.currentGuidId)))
              val revision = Guid(s.deltaId.clientId, s.deltaId.clientDeltaId, WithinDeltaId(s.currentGuidId + 1))

              // Make the data item
              val createDIO = create(id.asInstanceOf[Id[U with A]])
              // Remember to increment guid twice for the guid and revision we generated
              val stateWithA: (StateData[U], A) = createDIO.foldMap(arrow).run(s.withNextGuidId.withNextGuidId).value

              // We know that Put requires A <: U,
              // so the instanceOfs are safe
              val newAddedRefs = AddedRef[U](id.asInstanceOf[Id[U]], stateWithA._2.asInstanceOf[U], revision) :: stateWithA._1.addedRefs
              (stateWithA._1.copy(addedRefs = newAddedRefs), stateWithA._2)
            })