Function step_count_from_checked 

pub fn step_count_from_checked<T: Step>(
    iter: impl IntoIterator,
    start: T,
) -> Option<T>

Consumes the iterator, counting the number of iterations, starting from a given value. This uses the Step trait to keep track of the count of iterations. Returns None if the count exceeded the capcity of the count type (T).

This function always fully consumes the iterator, even if None is returned.

Note: This function takes any implementation of IntoIterator, which includes iterators themselves.

Examples

Basic usage:

let arr = [1, 2, 3];
let count: Option<u16> = step_count_from_checked(arr, 2);
assert_eq!(count, Some(5));

Overflow:

let arr = [(); u8::MAX as usize - 1];
let count: Option<u8> = step_count_from_checked(arr, 2);
assert!(count.is_none());

Consumption:

let mut range = -2..=i8::MAX as isize;
let count: Option<i8> = step_count_from_checked(&mut range, -1);
assert!(count.is_none());
assert!(range.is_empty());