Function bicoro::map

pub fn map<'a, I: 'a, O: 'a, A: 'a, B: 'a, F: 'a>(
    co: Coroutine<'a, I, O, A>, 
    map: F
) -> Coroutine<'a, I, O, B> where
    F: FnOnce(A) -> B, 

Map the inner type of the coroutine

This is sugar of bind and result

use bicoro::*;
let co :Coroutine<i32,(),String> = map(receive(), |a| a.to_string());