pub fn maybe_empty_fallback_chain<A: IntoIterator, B: IntoIterator<Item = A::Item>>(
a: A,
b: Option<B>,
) -> EmptyFallbackChain<A::IntoIter, B::IntoIter> ⓘExpand description
Construct an EmptyFallbackChain iterator with the second one optionally “pre-emptively made
empty”
See IteratorExt::maybe_empty_fallback_chain for more information.