Adds echo server test.

benchmarks/rust/echo_server_over_redis/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "echo_server_over_redis"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+tokio = { version = "0.2", features = ["full"] }
+redis = { version = "0.21.5", features = ["tokio-comp"] }
+futures = "0.3"

benchmarks/rust/echo_server_over_redis/src/main.rs

@@ -0,0 +1,43 @@
+use tokio::net::TcpListener;
+use tokio::prelude::*;
+use futures::prelude::*;
+use std::rc::Rc;
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let mut listener = TcpListener::bind("127.0.0.1:55555").await?;
+    let client = redis::Client::open("redis://127.0.0.1/").unwrap();
+    let mut con = client.get_async_connection().await?;
+
+    loop {
+        let (mut socket, _) = listener.accept().await?;
+
+        tokio::spawn(async move {
+            let mut buf = [0; 1024];
+
+            // In a loop, read data from the socket and write the data back.
+            loop {
+                let n = match socket.read(&mut buf).await {
+                    // socket closed
+                    Ok(n) if n == 0 => return,
+                    Ok(n) => n,
+                    Err(e) => {
+                        eprintln!("failed to read from socket; err = {:?}", e);
+                        return;
+                    }
+                };
+
+                //let result =
+                //    redis::cmd("PING")
+                //    .arg("Message")
+                //    .query_async::<redis::aio::Connection, String>(&mut con).await;
+
+                // Write the data back
+                if let Err(e) = socket.write_all(&buf[0..n]).await {
+                    eprintln!("failed to write to socket; err = {:?}", e);
+                    return;
+                }
+            }
+        });
+    }
+}