Add tower-h2 and more macro

tower-h2/examples/client.rs

@@ -0,0 +1,49 @@
+#![feature(async_await)]
+
+use http::Request;
+use std::task::{Context, Poll};
+use tokio::net::TcpStream;
+use tokio_buf::BufStream;
+use tower_h2::Connection;
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let addr = "[::1]:8888".parse()?;
+    let io = TcpStream::connect(&addr).await?;
+
+    let mut svc = Connection::handshake(io).await?;
+
+    let req = Request::get(format!("http://{}", addr)).body(Body::from(Vec::new()))?;
+    let res = svc.send(req).await?;
+
+    println!("RESPONSE={:?}", res);
+
+    Ok(())
+}
+
+#[derive(Debug, Default, Clone)]
+struct Body(Vec<u8>);
+
+impl From<Vec<u8>> for Body {
+    fn from(t: Vec<u8>) -> Self {
+        Body(t)
+    }
+}
+
+impl BufStream for Body {
+    type Item = std::io::Cursor<Vec<u8>>;
+    type Error = std::io::Error;
+
+    fn poll_buf(&mut self, _cx: &mut Context<'_>) -> Poll<Option<Result<Self::Item, Self::Error>>> {
+        if self.0.is_empty() {
+            return None.into();
+        }
+
+        use std::{io, mem};
+
+        let bytes = mem::replace(&mut self.0, Default::default());
+        let buf = io::Cursor::new(bytes);
+
+        Some(Ok(buf)).into()
+    }
+}