message: Test SmallMap iterators are Sync + Send
diff: @@ -130,6 +130,16 @@ impl<K, V> DoubleEndedIterator for IntoIter<K, V> {
  def_double_ended_iter!();
  }
  +fn _assert_iterators_sync_send() {
  + fn assert_sync_send<T: Sync + Send>(_: T) {}
  + fn test_iter(iter: Iter<String, u32>) {
  + assert_sync_send(iter);
  + }
  + fn test_into_iter(iter: IntoIter<String, u32>) {
  + assert_sync_send(iter);
  + }
  +}
  +
  /// An memory-efficient key-value map with determinstic order.
  ///
  /// Provides the standard container operations, modelled most closely on `indexmap::IndexMap`, plus:
  