Add life anotation for iter method.

[wangzhen11aaa]

Hi,
I have thought life anotation for a while, when to add and when not. As a result, I did not have a clean rule to make this decision, while, I think that for iter method, It is good to add the life anonation. What do you think, Expect your answer.

[skyzh]

There should be no difference. The lifetime elision rule helps us write fewer explicit lifetimes.

[wangzhen11aaa]

There should be no difference. The lifetime elision rule helps us write fewer explicit lifetimes.
Do you have some rule to write some code that makes the cargo clippy happy?