message: docs(example): fix http_proxy comment
diff: @@ -18,8 +18,8 @@ type HttpClient = Client<hyper::client::HttpConnector>;
  // 2. config http_proxy in command line
  // $ export http_proxy=http://127.0.0.1:8100
  // $ export https_proxy=http://127.0.0.1:8100
  -// 3. send requests
  -// $ curl -i https://www.some_domain.com/
  +// 3. send requests (don't use a domain name)
  +// $ curl -i https://8.8.8.8
  #[tokio::main]
  async fn main() {
  let addr = SocketAddr::from(([127, 0, 0, 1], 8100));
  