signal: make Signal::poll_recv method public

tokio/src/signal/unix.rs

@@ -397,7 +397,41 @@ impl Signal {
  poll_fn(|cx| self.poll_recv(cx)).await
  }
 
- pub(crate) fn poll_recv(&mut self, cx: &mut Context<'_>) -> Poll<Option<()>> {
+ /// Polls to receive the next signal notification event, outside of an
+ /// `async` context.
+ ///
+ /// This method returns:
+ ///
+ /// * `Poll::Pending` if no signals are available but the channel is not
+ /// closed.
+ /// * `Poll::Ready(Some(()))` if a signal is available.
+ /// * `Poll::Ready(None)` if the channel has been closed and all signals
+ /// sent before it was closed have been received.
+ ///
+ /// # Examples
+ ///
+ /// Polling from a manually implemented future
+ ///
+ /// ```rust,no_run
+ /// use std::pin::Pin;
+ /// use std::future::Future;
+ /// use std::task::{Context, Poll};
+ /// use tokio::signal::unix::Signal;
+ ///
+ /// struct MyFuture {
+ /// signal: Signal,
+ /// }
+ ///
+ /// impl Future for MyFuture {
+ /// type Output = Option<()>;
+ ///
+ /// fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+ /// println!("polling MyFuture");
+ /// self.signal.poll_recv(cx)
+ /// }
+ /// }
+ /// ```
+ pub fn poll_recv(&mut self, cx: &mut Context<'_>) -> Poll<Option<()>> {
  self.rx.poll_recv(cx)
  }