docs: private byte[] handleHeartbeat(Address address, byte[] message) {
      GossipMember remoteMember = SERIALIZER.decode(message);
      LOGGER.trace("{} - Received heartbeat: {}", localMember.id(), remoteMember);
      failureDetectors.computeIfAbsent(remoteMember.id(), n -> new PhiAccrualFailureDetector()).report();
      updateMember(remoteMember, true);
  
      // Return only reachable members to avoid populating removed members on remote nodes from unreachable members.
      return SERIALIZER.encode(Lists.newArrayList(members.values()
          .stream()
          .filter(member -> member.isReachable())
          .collect(Collectors.toList())));
    }