private static int getUniqueId(final int id) {
    final boolean specialCase =
        Boolean.getBoolean(GeodeGlossary.GEMFIRE_PREFIX + "SPECIAL_DURABLE");
    final String durableID = system.getProperties().getProperty(DURABLE_CLIENT_ID);
    if (specialCase && durableID != null && (!durableID.equals(""))) {
      return durable_synch_counter;
    } else {
      return id;
    }
  }
method to obtain ClientProxyMembership for client side
geode-core/src/main/java/org/apache/geode/internal/cache/tier/sockets/ClientProxyMembershipID.java