无法返回Chars迭代器,因为它"活不够久"

我希望能够将一个Chars迭代器分配给一个结构,String该结构是在struct的"constructor"方法中创建的.我该怎么做呢？

代码(运行它):

use std::str::Chars;

fn main() {
    let foo = Foo::new();
}

struct Foo<'a> {
    chars: Chars<'a>
}
impl<'a> Foo<'a> {
    pub fn new() -> Self {
        let s = "value".to_string();
        Foo { chars: s.chars() }
    }
}

错误:

error: `s` does not live long enough
  --> :13:22
13 |>         Foo { chars: s.chars() }
   |>                      ^
note: reference must be valid for the lifetime 'a as defined on the block at 11:25...
  --> :11:26
11 |>     pub fn new() -> Self {
   |>                          ^
note: ...but borrowed value is only valid for the block suffix following statement 0 at 12:36
  --> :12:37
12 |>         let s = "value".to_string();
   |>