Don't enable trace logging in the test by default

This makes the test really slow. For debugging purposes it can
still be enabled via CLI.

quinn/src/tests.rs

@@ -16,6 +16,7 @@ use tokio::{
 };
 use tracing::{info, info_span};
 use tracing_futures::Instrument as _;
+use tracing_subscriber::EnvFilter;
 
 use super::{
     ClientConfigBuilder, Endpoint, Incoming, NewConnection, RecvStream, SendStream,
@@ -486,7 +487,7 @@ fn gen_data(size: usize, seed: u64) -> Vec<u8> {
 
 pub fn subscribe() -> tracing::subscriber::DefaultGuard {
     let sub = tracing_subscriber::FmtSubscriber::builder()
-        .with_env_filter("quinn=trace")
+        .with_env_filter(EnvFilter::from_default_env())
         .with_writer(|| TestWriter)
         .finish();
     tracing::subscriber::set_default(sub)