Refactor initializing tracing-subscriber

examples/testing/src/main.rs

@@ -9,16 +9,14 @@ use axum::{
     Json, Router,
 };
 use tower_http::trace::TraceLayer;
-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_testing=debug,tower_http=debug".into()),
-        ))
-        .with(tracing_subscriber::fmt::layer())
+        )
         .init();
 
     let addr = std::net::SocketAddr::from(([127, 0, 0, 1], 3000));