/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub trait ExactSizeIterator: Iterator {
- /// Returns the exact number of times the iterator will iterate.
+ /// Returns the exact length of the iterator.
///
+ /// The implementation ensures that the iterator will return exactly `len()`
+ /// more times a `Some(T)` value, before returning `None`.
/// This method has a default implementation, so you usually should not
/// implement it directly. However, if you can provide a more efficient
/// implementation, you can do so. See the [trait-level] docs for an