diff --git a/gm-quic/examples/client.rs b/gm-quic/examples/client.rs
index d9c3a197..acbdb462 100644
--- a/gm-quic/examples/client.rs
+++ b/gm-quic/examples/client.rs
@@ -27,11 +27,12 @@ struct Arguments {
 fn main() {
     let args = Arguments::parse();
     let code = {
-        if let Err(e) = run(args) {
-            eprintln!("ERROR: {e}");
-            1
-        } else {
-            0
+        match run(args) {
+            Err(e) => {
+                eprintln!("ERROR: {e}");
+                1
+            }
+            _ => 0,
         }
     };
     ::std::process::exit(code);
diff --git a/gm-quic/examples/server.rs b/gm-quic/examples/server.rs
index c346a71a..07eef1ed 100644
--- a/gm-quic/examples/server.rs
+++ b/gm-quic/examples/server.rs
@@ -21,11 +21,12 @@ struct Opt {
 fn main() {
     let opt = Opt::parse();
     let code = {
-        if let Err(e) = run(opt) {
-            eprintln!("ERROR: {e}");
-            1
-        } else {
-            0
+        match run(opt) {
+            Err(e) => {
+                eprintln!("ERROR: {e}");
+                1
+            }
+            _ => 0,
         }
     };
     ::std::process::exit(code);
@@ -44,7 +45,7 @@ async fn run(options: Opt) -> Result<(), Box<dyn std::error::Error>> {
         .with_supported_versions([0x00000001u32])
         .without_cert_verifier()
         // .keep_alive()
-        .with_single_cert(options.cert, options.key)
+        .with_single_cert(options.cert.as_path(), options.key.as_path())
         .listen(options.bind)?;
 
     while let Ok((_conn, pathway)) = server.accept().await {
diff --git a/gm-quic/src/util.rs b/gm-quic/src/util.rs
index 1c86f530..dd0cd0c9 100644
--- a/gm-quic/src/util.rs
+++ b/gm-quic/src/util.rs
@@ -2,38 +2,36 @@ use std::path::Path;
 
 use rustls::pki_types::{pem::PemObject, CertificateDer, PrivateKeyDer};
 
-pub struct Certificate(Vec<CertificateDer<'static>>);
-
-impl From<Vec<CertificateDer<'static>>> for Certificate {
-    fn from(cert: Vec<CertificateDer<'static>>) -> Self {
-        Self(cert)
-    }
-}
-
 pub trait ToCertificate {
     fn to_certificate(self) -> Vec<CertificateDer<'static>>;
 }
 
-impl ToCertificate for Certificate {
+impl ToCertificate for Vec<CertificateDer<'static>> {
     fn to_certificate(self) -> Vec<CertificateDer<'static>> {
-        self.0
+        self
     }
 }
 
-impl<P: AsRef<Path>> ToCertificate for P {
+impl ToCertificate for &Path {
     fn to_certificate(self) -> Vec<CertificateDer<'static>> {
-        CertificateDer::pem_file_iter(self.as_ref())
+        CertificateDer::pem_file_iter(self)
             .expect("failed to open cert file")
             .collect::<Result<Vec<_>, _>>()
             .expect("failed to parse cert file")
     }
 }
 
-pub struct PrivateKey(PrivateKeyDer<'static>);
+impl ToCertificate for &[u8] {
+    fn to_certificate(self) -> Vec<CertificateDer<'static>> {
+        CertificateDer::pem_slice_iter(self)
+            .collect::<Result<Vec<_>, _>>()
+            .expect("failed to parse cert file")
+    }
+}
 
-impl From<PrivateKeyDer<'static>> for PrivateKey {
-    fn from(key: PrivateKeyDer<'static>) -> Self {
-        Self(key)
+impl<const N: usize> ToCertificate for &[u8; N] {
+    fn to_certificate(self) -> Vec<CertificateDer<'static>> {
+        <&[u8]>::to_certificate(self)
     }
 }
 
@@ -41,14 +39,26 @@ pub trait ToPrivateKey {
     fn to_private_key(self) -> PrivateKeyDer<'static>;
 }
 
-impl ToPrivateKey for PrivateKey {
+impl ToPrivateKey for PrivateKeyDer<'static> {
+    fn to_private_key(self) -> PrivateKeyDer<'static> {
+        self
+    }
+}
+
+impl ToPrivateKey for &Path {
+    fn to_private_key(self) -> PrivateKeyDer<'static> {
+        PrivateKeyDer::from_pem_file(self).expect("failed to parse private key file")
+    }
+}
+
+impl ToPrivateKey for &[u8] {
     fn to_private_key(self) -> PrivateKeyDer<'static> {
-        self.0
+        PrivateKeyDer::from_pem_slice(self).expect("failed to parse private key file")
     }
 }
 
-impl<P: AsRef<Path>> ToPrivateKey for P {
+impl<const N: usize> ToPrivateKey for &[u8; N] {
     fn to_private_key(self) -> PrivateKeyDer<'static> {
-        PrivateKeyDer::from_pem_file(self.as_ref()).expect("failed to parse private key file")
+        <&[u8]>::to_private_key(self)
     }
 }
diff --git a/h3-shim/examples/h3-server.rs b/h3-shim/examples/h3-server.rs
index fb4b4382..14021225 100644
--- a/h3-shim/examples/h3-server.rs
+++ b/h3-shim/examples/h3-server.rs
@@ -95,7 +95,7 @@ pub async fn run(opt: Opt) -> Result<(), Box<dyn std::error::Error + Send + Sync
         .without_cert_verifier()
         .with_parameters(params)
         .enable_sni()
-        .add_host("localhost", cert, key)
+        .add_host("localhost", cert.as_path(), key.as_path())
         .with_alpns([ALPN.to_vec()])
         .listen(&opt.listen[..])?;
     info!("listening on {:?}", quic_server.addresses());
diff --git a/qbase/src/util/bound_deque.rs b/qbase/src/util/bound_deque.rs
index 2ac60a95..a45a22dc 100644
--- a/qbase/src/util/bound_deque.rs
+++ b/qbase/src/util/bound_deque.rs
@@ -105,12 +105,15 @@ impl<T> futures::Stream for Receiver<T> {
         if queue.capacity() == 0 {
             return Poll::Ready(None);
         }
-        if let Some(item) = queue.pop_front() {
-            self.inner.write_waker.wake();
-            Poll::Ready(Some(item))
-        } else {
-            self.inner.read_waker.register(cx.waker());
-            Poll::Pending
+        match queue.pop_front() {
+            Some(item) => {
+                self.inner.write_waker.wake();
+                Poll::Ready(Some(item))
+            }
+            _ => {
+                self.inner.read_waker.register(cx.waker());
+                Poll::Pending
+            }
         }
     }
 }
diff --git a/qconnection/src/builder.rs b/qconnection/src/builder.rs
index e9f43f4e..9022b34c 100644
--- a/qconnection/src/builder.rs
+++ b/qconnection/src/builder.rs
@@ -419,7 +419,7 @@ impl ComponentsReady {
     }
 }
 
-fn accpet_transport_parameters(components: &Components) -> impl Future<Output = ()> + Send {
+fn accpet_transport_parameters(components: &Components) -> impl Future<Output = ()> + Send + use<> {
     let params = components.parameters.clone();
     let streams = components.spaces.data().streams().clone();
     let cid_registry = components.cid_registry.clone();
diff --git a/qconnection/src/lib.rs b/qconnection/src/lib.rs
index 580fa5cf..24a946b3 100644
--- a/qconnection/src/lib.rs
+++ b/qconnection/src/lib.rs
@@ -175,7 +175,7 @@ pub struct Components {
 impl Components {
     pub fn open_bi_stream(
         &self,
-    ) -> impl Future<Output = io::Result<Option<(StreamId, (StreamReader, StreamWriter))>>> + Send
+    ) -> impl Future<Output = io::Result<Option<(StreamId, (StreamReader, StreamWriter))>>> + Send + use<>
     {
         let params = self.parameters.clone();
         let streams = self.spaces.data().streams().clone();
@@ -193,7 +193,7 @@ impl Components {
 
     pub fn open_uni_stream(
         &self,
-    ) -> impl Future<Output = io::Result<Option<(StreamId, StreamWriter)>>> + Send {
+    ) -> impl Future<Output = io::Result<Option<(StreamId, StreamWriter)>>> + Send + use<> {
         let params = self.parameters.clone();
         let streams = self.spaces.data().streams().clone();
         let send_notify = self.send_notify.clone();
@@ -209,7 +209,7 @@ impl Components {
 
     pub fn accept_bi_stream(
         &self,
-    ) -> impl Future<Output = io::Result<Option<(StreamId, (StreamReader, StreamWriter))>>> + Send
+    ) -> impl Future<Output = io::Result<Option<(StreamId, (StreamReader, StreamWriter))>>> + Send + use<>
     {
         let params = self.parameters.clone();
         let streams = self.spaces.data().streams().clone();
@@ -227,7 +227,7 @@ impl Components {
 
     pub fn accept_uni_stream(
         &self,
-    ) -> impl Future<Output = io::Result<Option<(StreamId, StreamReader)>>> + Send {
+    ) -> impl Future<Output = io::Result<Option<(StreamId, StreamReader)>>> + Send + use<> {
         let streams = self.spaces.data().streams().clone();
         async move { Ok(Some(streams.accept_uni().await?)) }
     }
@@ -236,7 +236,9 @@ impl Components {
         self.spaces.data().datagrams().reader()
     }
 
-    pub fn unreliable_writer(&self) -> impl Future<Output = io::Result<UnreliableWriter>> + Send {
+    pub fn unreliable_writer(
+        &self,
+    ) -> impl Future<Output = io::Result<UnreliableWriter>> + Send + use<> {
         let params = self.parameters.clone();
         let datagrams = self.spaces.data().datagrams().clone();
         async move {
diff --git a/qconnection/src/path/burst.rs b/qconnection/src/path/burst.rs
index b8dbebf1..b56a365f 100644
--- a/qconnection/src/path/burst.rs
+++ b/qconnection/src/path/burst.rs
@@ -48,7 +48,7 @@ impl Burst {
     fn prepare_buffers<'b>(
         &self,
         buffers: &'b mut Vec<Vec<u8>>,
-    ) -> io::Result<impl Iterator<Item = &'b mut [u8]>> {
+    ) -> io::Result<impl Iterator<Item = &'b mut [u8]> + use<'b>> {
         let max_segments = self.path.interface.max_segments()?;
         let max_segment_size = self.path.interface.max_segment_size()?;
 
diff --git a/qconnection/src/path/idle.rs b/qconnection/src/path/idle.rs
index 644c3967..1580297b 100644
--- a/qconnection/src/path/idle.rs
+++ b/qconnection/src/path/idle.rs
@@ -19,7 +19,10 @@ impl super::Path {
         }
     }
 
-    pub fn idle_timeout(self: &Arc<Self>, components: &Components) -> impl Future<Output = ()> {
+    pub fn idle_timeout(
+        self: &Arc<Self>,
+        components: &Components,
+    ) -> impl Future<Output = ()> + use<> {
         let parameters = components.parameters.clone();
         let this = self.clone();
         async move {
diff --git a/qconnection/src/tls.rs b/qconnection/src/tls.rs
index 1264bc74..6434e41e 100644
--- a/qconnection/src/tls.rs
+++ b/qconnection/src/tls.rs
@@ -215,7 +215,7 @@ impl ArcTlsSession {
 
 /// Start the TLS handshake, automatically upgrade the keys, and transmit tls data.
 #[tracing::instrument(level = "trace", skip(components))]
-pub fn keys_upgrade(components: &Components) -> impl Future<Output = ()> + Send {
+pub fn keys_upgrade(components: &Components) -> impl Future<Output = ()> + Send + use<> {
     let crypto_streams: [&CryptoStream; 3] = [
         components.spaces.initial().crypto_stream(),
         components.spaces.handshake().crypto_stream(),
diff --git a/qrecovery/src/journal/sent.rs b/qrecovery/src/journal/sent.rs
index 7394f793..ec4e9ef9 100644
--- a/qrecovery/src/journal/sent.rs
+++ b/qrecovery/src/journal/sent.rs
@@ -212,12 +212,12 @@ impl<T: Clone> RotateGuard<'_, T> {
     }
 
     /// Called when the packet sent is acked by peer, return the frames in that packet.
-    pub fn on_pkt_acked(&mut self, pn: u64) -> impl Iterator<Item = T> + '_ {
+    pub fn on_pkt_acked(&mut self, pn: u64) -> impl Iterator<Item = T> + '_ + use<'_, T> {
         self.inner.on_pkt_acked(pn)
     }
 
     /// Called when the packet sent may lost, reutrn the frames in that packet.
-    pub fn may_loss_pkt(&mut self, pn: u64) -> impl Iterator<Item = T> + '_ {
+    pub fn may_loss_pkt(&mut self, pn: u64) -> impl Iterator<Item = T> + '_ + use<'_, T> {
         self.inner.may_loss_pkt(pn)
     }