example-service: set max frame length to usize::MAX

I don't know what the intention was behind using u32::MAX + 1 but since the
argument's type is usize this is the only giant value that makes sense to me.

example-service/src/server.rs

@@ -58,7 +58,7 @@ async fn main() -> io::Result<()> {
     // JSON transport is provided by the json_transport tarpc module. It makes it easy
     // to start up a serde-powered json serialization strategy over TCP.
     let mut listener = tarpc::serde_transport::tcp::listen(&server_addr, Json::default).await?;
-    listener.config_mut().max_frame_length(4294967296);
+    listener.config_mut().max_frame_length(usize::MAX);
     listener
         // Ignore accept errors.
         .filter_map(|r| future::ready(r.ok()))