フリー問題

問題文

A lambda handed to a middle step reads and updates a variable that lives outside the chain. What do the rules say about the outcome?

選択肢

1. The outcome may be held back until a barrier lifts because such a lambda depends on something that shifts underneath it.
2. The outcome may be slower yet faithful to its order because such a lambda depends on something that shifts underneath it.
3. The outcome may be correct after a second traversal of it because such a lambda depends on something that shifts underneath it.
4. The outcome may be wrong or unpredictable because such a lambda depends on something that shifts underneath it.