use std::convert::Infallible;
use std::pin::Pin;

#[derive(Clone, Copy)]
pub struct DummySink {}

impl<T> futures::Sink<T> for DummySink {
    type Error = Infallible;

    fn poll_ready(
        self: Pin<&mut Self>,
        _cx: &mut futures::task::Context<'_>,
    ) -> futures::task::Poll<Result<(), Infallible>> {
        futures::task::Poll::Ready(Ok(()))
    }

    fn start_send(self: Pin<&mut Self>, _item: T) -> Result<(), Infallible> {
        Ok(())
    }
    fn poll_flush(
        self: Pin<&mut Self>,
        _cx: &mut futures::task::Context<'_>,
    ) -> futures::task::Poll<Result<(), Infallible>> {
        futures::task::Poll::Ready(Ok(()))
    }
    fn poll_close(
        self: Pin<&mut Self>,
        _cx: &mut futures::task::Context<'_>,
    ) -> futures::task::Poll<Result<(), Infallible>> {
        futures::task::Poll::Ready(Ok(()))
    }
}