Function cubist_proxy::transformer::convert_fut

pub fn convert_fut<Si, Ri, Ei, So, Ro, Eo, Ffr, Ffs>(
    pair: impl Pair<Si, Ri, Ei>,
    fr: impl Fn(Result<Ri, Ei>) -> Ffr + Send,
    fs: impl Fn(Result<So, Eo>) -> Ffs + Send
) -> impl Pair<So, Ro, Eo>where
    Ffr: Future<Output = Result<Ro, Eo>> + Send,
    Ffs: Future<Output = Result<Si, Ei>> + Send,

Apply a pair of future-returning conversions to a Pair, returning another Pair

Any errors in conversion will be returned from the Stream / sent into the Sink