message: Simplify destroy_iterators implementation
diff: @@ -379,10 +379,7 @@ unsafe fn get_data<S: Storage, Q: Querier>(ptr: *mut c_void) -> Box<ContextData<
  #[cfg(feature = "iterator")]
  fn destroy_iterators<S: Storage, Q: Querier>(context: &mut ContextData<S, Q>) {
  - let keys: Vec<u32> = context.iter.keys().cloned().collect();
  - for key in keys {
  - let _ = context.iter.remove(&key);
  - }
  + context.iter.clear();
  }
  #[cfg(not(feature = "iterator"))]
  