如何在StackVec上实现IntoIterator

pub struct StackVecIterator<T> {
    stack_vec: StackVec<T>,
    index: usize,
}

impl<T> Iterator for StackVecIterator<T> {
    type Item = T;

    fn next(&mut self) -> Option<Self::Item> {
        if self.index < self.stack_vec.len() {
            let item = self.stack_vec[self.index];
            self.index += 1;
            Some(item)
        } else {
            None
        }
    }
}

impl<T> IntoIterator for StackVec<T> {
    type Item = T;
    type IntoIter = StackVecIterator<T>;

    fn into_iter(self) -> Self::IntoIter {
        StackVecIterator {
            stack_vec: self,
            index: 0,
        }
    }
}

let stack_vec: StackVec<i32> = StackVec::new();
stack_vec.push(1);
stack_vec.push(2);
stack_vec.push(3);

for item in stack_vec {
    println!("{}", item);
}

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