message: [metric]:add process metric on linux
diff: @@ -53,6 +53,13 @@ pub fn start_server(host: String, port: u16) {
  .next()
  .unwrap();
  + // metric process info.
  + #[cfg(target_os = "linux")]
  + prometheus::register(Box::new(
  + prometheus::process_collector::ProcessCollector::for_self(),
  + ))
  + .unwrap();
  +
  thread::spawn(move || {
  let make_service =
  make_service_fn(|_| future::ok::<_, hyper::Error>(service_fn(serve_metrics)));
  