feat: tokio stream

__concurrent/async_study/examples/tokio_stream.rs

@@ -0,0 +1,10 @@
+use tokio_stream::{self as stream, StreamExt};
+
+#[tokio::main]
+async fn main() {
+    let mut stream = stream::iter(vec![0, 1, 2]);
+
+    while let Some(value) = stream.next().await {
+        println!("Got {}", value);
+    }
+}

__concurrent/async_study/examples/tokio_stream2.rs

@@ -0,0 +1,29 @@
+use std::pin::Pin;
+use std::task::{Context, Poll};
+
+use futures_core::Stream;
+use tokio_stream::StreamExt;
+
+#[tokio::main]
+async fn main() {
+    let mut stream = MyStream(0);
+
+    while let Some(value) = stream.next().await {
+        println!("Got {}", value);
+    }
+}
+
+struct MyStream(i32);
+
+impl Stream for MyStream {
+    type Item = i32;
+
+    fn poll_next(mut self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        if self.0 < 10 {
+            self.0 += 1;
+            Poll::Ready(Some(self.0))
+        } else {
+            Poll::Ready(None)
+        }
+    }
+}