util: add examples for FramedRead and FramedWrite

tokio-util/src/codec/framed_read.rs

@@ -14,6 +14,27 @@ use std::task::{Context, Poll};
 pin_project! {
     /// A [`Stream`] of messages decoded from an [`AsyncRead`].
     ///
+    /// # Examples
+    /// ```
+    /// use tokio_stream::StreamExt;
+    /// use tokio_util::codec::LinesCodec;
+    /// use tokio_util::codec::FramedRead;
+    ///
+    /// #[tokio::main]
+    /// async fn main() {
+    ///     let message = "Hello\nWorld".as_bytes();
+    ///     let decoder = LinesCodec::new();
+    ///     let mut reader = FramedRead::new(message, decoder);
+    ///
+    ///     let frame1 = reader.next().await.unwrap().unwrap();
+    ///     let frame2 = reader.next().await.unwrap().unwrap();
+    ///
+    ///     assert!(reader.next().await.is_none());
+    ///     assert_eq!(frame1, "Hello");
+    ///     assert_eq!(frame2, "World");
+    /// }
+    /// ```
+    ///
     /// [`Stream`]: futures_core::Stream
     /// [`AsyncRead`]: tokio::io::AsyncRead
     pub struct FramedRead<T, D> {

tokio-util/src/codec/framed_write.rs

@@ -15,6 +15,30 @@ use std::task::{Context, Poll};
 pin_project! {
     /// A [`Sink`] of frames encoded to an `AsyncWrite`.
     ///
+    /// # Examples
+    /// ```
+    /// use futures::sink::SinkExt;
+    /// use tokio_util::codec::LinesCodec;
+    /// use tokio_util::codec::FramedWrite;
+    ///
+    /// #[tokio::main]
+    /// async fn main() {
+    ///     let messages = vec!["Hello", "World"];
+    ///
+    ///     let buffer = Vec::new();
+    ///     let encoder = LinesCodec::new();
+    ///     let mut writer = FramedWrite::new(buffer, encoder);
+    ///
+    ///     for message in &messages {
+    ///         writer.send(message).await.unwrap();
+    ///     }
+    ///
+    ///     let buffer = writer.get_ref();
+    ///
+    ///     assert_eq!(buffer.as_slice(), "Hello\nWorld\n".as_bytes());
+    /// }
+    /// ```
+    ///
     /// [`Sink`]: futures_sink::Sink
     pub struct FramedWrite<T, E> {
         #[pin]