message: avoid substraction overflow on negative level
diff: // SPDX-License-Identifier: MIT
  use std::{
  + cmp,
  collections::{BTreeMap, BTreeSet, VecDeque},
  net::SocketAddr,
  };
  @@ -196,7 +197,7 @@ pub fn bootstrap_reducer(state: &mut State, action: &ActionWithMeta) {
  peer_intervals,
  ..
  } => {
  - let level = content.current_head.header.level();
  + let level = cmp::max(0, content.current_head.header.level());
  let hash = &content.current_head.hash;
  let is_same_chain = if *main_chain_last_level >= level {
  let index = *main_chain_last_level - level;
  