async fn serve_conn<C: JsonRpcCodec>(
server: Arc<Server>,
stream: TcpStream,
peer_addr: SocketAddr,
codec: C,
) -> Result<()>async fn serve_conn<C: JsonRpcCodec>(
server: Arc<Server>,
stream: TcpStream,
peer_addr: SocketAddr,
codec: C,
) -> Result<()>