Refactor initializing tracing-subscriber

examples/http-proxy/src/main.rs

@@ -23,16 +23,14 @@ use hyper::upgrade::Upgraded;
 use std::net::SocketAddr;
 use tokio::net::TcpStream;
 use tower::{make::Shared, ServiceExt};
-use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
 
 #[tokio::main]
 async fn main() {
-    tracing_subscriber::registry()
-        .with(tracing_subscriber::EnvFilter::new(
-            std::env::var("RUST_LOG")
+    tracing_subscriber::fmt()
+        .with_env_filter(
+            tracing_subscriber::EnvFilter::try_from_default_env()
                 .unwrap_or_else(|_| "example_http_proxy=trace,tower_http=debug".into()),
-        ))
-        .with(tracing_subscriber::fmt::layer())
+        )
         .init();
 
     let router_svc = Router::new().route("/", get(|| async { "Hello, World!" }));