use crate::*;
/// The [`Lender`] version of [`core::iter::FusedIterator`].
///
/// A lender that always continues to yield `None` when exhausted.
///
/// Calling [`next`](Lender::next) on a fused lender that has returned `None`
/// once is guaranteed to return `None` again.
/// Marker trait that ensures that a fallible lender will always continue to
/// yield `Ok(None)` once it has already returned `Ok(None)`. After an error,
/// the behavior is implementation-defined.