Function first 

pub fn first<I, T>(iter: I) -> Option<T>
where
    I: Iterator<Item = T>,

Returns the first element from an iterator

Example

use polyglot_sql::helper::first;
use std::collections::HashSet;

let set = HashSet::from([1, 2, 3]);
let f = first(set.iter());
assert!(f.is_some());