public readonly bool MoveNext <TCollection>(
     TCollection blocks,
     ref TraversalEnumerationState state)
     where TCollection : IReadOnlyList <BasicBlock> =>
 TraversalOrder.BackwardsMoveNext(ref state);
 public readonly TraversalEnumerationState Init <TCollection>(TCollection blocks)
     where TCollection : IReadOnlyList <BasicBlock> =>
 TraversalOrder.BackwardsInit(blocks);