first

Function first 

Source
pub fn first<T>(
    iter: &mut Box<dyn Iterator<Item = Result<T, Error>>>,
    default: Option<T>,
) -> Option<Result<T, Error>>
where T: 'static + Clone,
Expand description

https://more-itertools.readthedocs.io/en/v10.2.0/_modules/more_itertools/more.html#first