message: avoid drain of vec
diff: @@ -227,9 +227,9 @@ impl Tree {
  }
  }
  - let mut new_root = peaks.drain(0..1).nth(0).expect("At lest 2 elements in peaks");
  + let mut new_root = *peaks.iter().nth(0).expect("At lest 2 elements in peaks");
  - for next_peak in peaks.into_iter() {
  + for next_peak in peaks.into_iter().skip(1) {
  new_root = self.push_generated(
  combine_nodes(
  self.resolve_link(new_root)?,
  