docs: public List<Peer> findPeersWithServiceMask(int mask) {
          lock.lock();
          try {
              ArrayList<Peer> results = new ArrayList<>(peers.size());
              for (Peer peer : peers)
                  if ((peer.getPeerVersionMessage().localServices & mask) == mask)
                      results.add(peer);
              return results;
          } finally {
              lock.unlock();
          }
      }