Function select5

pub fn select5<A, B, C, D, E>(
    a: A,
    b: B,
    c: C,
    d: D,
    e: E,
) -> Select5<A, B, C, D, E> 
where
    A: Future,
    B: Future,
    C: Future,
    D: Future,
    E: Future,

Same as select, but with more futures.