Function futures_async_combinators::future::and_then

pub async fn and_then<FutA, FutB, F, T, U, E>(
    future: FutA, 
    f: F
) -> Result<U, E> where
    F: FnOnce(T) -> FutB,
    FutA: Future<Output = Result<T, E>>,
    FutB: Future<Output = Result<U, E>>,