message: Make Connection Cloneable
diff: @@ -408,7 +408,7 @@ impl<TypeState> ConnectionOptions<TypeState> {
  let shared_state = SharedState::connect(options, nats_url)?;
  let conn = Connection {
  - sid: AtomicUsize::new(1),
  + sid: Arc::new(AtomicUsize::new(1)),
  shutdown_dropper: Arc::new(ShutdownDropper {
  shared_state: shared_state.clone(),
  }),
  @@ -455,11 +455,11 @@ impl Drop for ShutdownDropper {
  }
  /// A NATS connection.
  -#[derive(Debug)]
  +#[derive(Debug, Clone)]
  pub struct Connection {
  shared_state: Arc<SharedState>,
  shutdown_dropper: Arc<ShutdownDropper>,
  - sid: AtomicUsize,
  + sid: Arc<AtomicUsize>,
  }
  #[derive(Serialize, Clone, Debug)]
  