refactor: pass ALPN around as &str

src/net.rs

@@ -127,7 +127,7 @@ pub(crate) async fn connect_tls_inner(
     addr: SocketAddr,
     host: &str,
     strict_tls: bool,
-    alpn: &[&str],
+    alpn: &str,
 ) -> Result<impl SessionStream + 'static> {
     let tcp_stream = connect_tcp_inner(addr).await?;
     let tls_stream = wrap_tls(strict_tls, host, alpn, tcp_stream).await?;