fn new<F>(buffer: B, f: F) -> Self

    fn new<F>(buffer: B, mut f: F) -> Self

        F: Fn(B::Data) -> () + Send + 'static,

        F: FnMut(B::Data) -> () + Send + 'static,

        F: Fn(T) -> () + Send + 'static,

        F: FnMut(T) -> () + Send + 'static,

        F: Fn(T) -> () + Send + 'static,

        F: FnMut(T) -> () + Send + 'static,