message: Do not return any effects after sync done.
diff: @@ -266,6 +266,7 @@ impl<I: Clone + PartialEq + 'static> LinearChainSync<I> {
  );
  if self.is_chain_end(&block) {
  self.mark_done();
  + return Effects::new()
  }
  match block.header().next_era_validator_weights() {
  None => (),
  