chore: remove unused future/pending.rs (#2860)

tokio/src/future/pending.rs

@@ -1,44 +0,0 @@
-use sdt::pin::Pin;
-use std::future::Future;
-use std::marker;
-use std::task::{Context, Poll};
-
-/// Future for the [`pending()`] function.
-#[derive(Debug)]
-#[must_use = "futures do nothing unless you `.await` or poll them"]
-struct Pending<T> {
-    _data: marker::PhantomData<T>,
-}
-
-/// Creates a future which never resolves, representing a computation that never
-/// finishes.
-///
-/// The returned future will forever return [`Poll::Pending`].
-///
-/// # Examples
-///
-/// ```no_run
-/// use tokio::future;
-///
-/// #[tokio::main]
-/// async fn main {
-///     future::pending().await;
-///     unreachable!();
-/// }
-/// ```
-pub async fn pending() -> ! {
-    Pending {
-        _data: marker::PhantomData,
-    }
-    .await
-}
-
-impl<T> Future for Pending<T> {
-    type Output = !;
-
-    fn poll(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<T> {
-        Poll::Pending
-    }
-}
-
-impl<T> Unpin for Pending<T> {}