message: rt -> runtime
diff: @@ -45,8 +45,8 @@ pub fn dev(
  thread::spawn(move || socket::listen(session_id));
  - let mut rt = TokioRuntime::new()?;
  - rt.block_on(serve(server_config, preview_id))?;
  + let mut runtime = TokioRuntime::new()?;
  + runtime.block_on(serve(server_config, preview_id))?;
  Ok(())
  }
  