message: Make message fields public
diff: @@ -469,9 +469,9 @@ pub async fn connect<T: ToSocketAddrs>(addr: T) -> Result<Client, io::Error> {
  #[derive(Debug)]
  pub struct Message {
  - subject: String,
  - reply_to: Option<String>,
  - payload: Bytes,
  + pub subject: String,
  + pub reply_to: Option<String>,
  + pub payload: Bytes,
  }
  pub struct Subscriber {
  