Move delay method to FutureExt::delay

src/future/future.rs

@@ -105,6 +105,28 @@ extension_trait! {
     }
 
     pub trait FutureExt: std::future::Future {
+        /// Creates a future that is delayed before it starts yielding items.
+        ///
+        /// # Examples
+        ///
+        /// ```
+        /// # async_std::task::block_on(async {
+        /// use async_std::future;
+        /// use std::time::Duration;
+        /// use async_std::future::FutureExt;
+        ///
+        /// let a = future::ready(1).delay(Duration::from_millis(2000));
+        /// dbg!(a.await);
+        /// # })
+        /// ```
+        #[cfg_attr(feature = "docs", doc(cfg(unstable)))]
+        #[cfg(any(feature = "unstable", feature = "docs"))]
+        fn delay(self, dur: Duration) -> DelayFuture<Self>
+        where
+            Self: Future + Sized
+        {
+            DelayFuture::new(self, dur)
+        }
     }
 
     impl<F: Future + Unpin + ?Sized> Future for Box<F> {

src/future/future/delay.rs

@@ -6,28 +6,6 @@ use futures_timer::Delay;
 use crate::future::Future;
 use crate::task::{Context, Poll};
 
-/// Creates a future that is delayed before it starts yielding items.
-///
-/// # Examples
-///
-/// ```
-/// # async_std::task::block_on(async {
-/// use async_std::future;
-/// use std::time::Duration;
-
-/// let a = future::delay(future::ready(1) ,Duration::from_millis(2000));
-/// dbg!(a.await);
-/// # })
-/// ```
-#[cfg_attr(feature = "docs", doc(cfg(unstable)))]
-#[cfg(any(feature = "unstable", feature = "docs"))]
-pub fn delay<F>(f: F, dur: Duration) -> DelayFuture<F>
-where
-    F: Future,
-{
-    DelayFuture::new(f, dur)
-}
-
 #[doc(hidden)]
 #[derive(Debug)]
 pub struct DelayFuture<F> {

src/future/mod.rs

@@ -51,6 +51,7 @@ pub use async_macros::{select, try_select};
 use cfg_if::cfg_if;
 
 pub use future::Future;
+pub use future::FutureExt;
 pub use pending::pending;
 pub use poll_fn::poll_fn;
 pub use ready::ready;
@@ -65,9 +66,7 @@ mod timeout;
 cfg_if! {
     if #[cfg(any(feature = "unstable", feature = "docs"))] {
         mod into_future;
-        mod delay;
 
         pub use into_future::IntoFuture;
-        pub use delay::delay;
     }
 }