message: trace: fix counters example, Span IDs must be greater than zero
  ## Motivation
  tokio-trace counter example was panicking due to returning 0 as the first Span Id
  ## Solution
  start ID's with 1 instead
diff: @@ -113,7 +113,7 @@ impl Counters {
  fn new() -> (Self, CounterSubscriber) {
  let counters = Counters(Arc::new(RwLock::new(HashMap::new())));
  let subscriber = CounterSubscriber {
  - ids: AtomicUsize::new(0),
  + ids: AtomicUsize::new(1),
  counters: counters.clone(),
  };
  (counters, subscriber)
  