class AbstractClientHandle extends LocalAbortable implements Identifiable<TransactionIdentifier> {

    final @Nullable Collection<T> ensureClosed() {
        @SuppressWarnings("unchecked")
        final State<T> local = STATE_UPDATER.getAndSet(this, null);
        return local == null ? null : local.values();
    }

      AbstractClientHandle(final AbstractClientHistory parent, final TransactionIdentifier transactionId);

}