code: private void addInstanceToMap(InstanceInfo info, String vipAddresses, Map<String, VipIndexSupport> vipMap) {
          if (vipAddresses != null) {
              String[] vipAddressArray = vipAddresses.toUpperCase(Locale.ROOT).split(",");
              for (String vipAddress : vipAddressArray) {
                  VipIndexSupport vis = vipMap.computeIfAbsent(vipAddress, k -> new VipIndexSupport());
                  vis.instances.add(info);
              }
          }
      }
docs: Add the instance to the given map based if the vip address matches with
  that of the instance. Note that an instance can be mapped to multiple vip
  addresses.