private static void handleRegExPR(final @NotNull PartitionedRegion region,
      final @NotNull String regex,
      final @NotNull InterestResultPolicy policy, final @NotNull ServerConnection servConn)
      throws IOException {
    final List<Object> keyList = new ArrayList<>(MAXIMUM_CHUNK_SIZE);
    region.getKeysWithRegEx(regex, sendTombstonesInRIResults(policy),
        theSet -> appendInterestResponseKeys(region, regex, uncheckedCast(theSet), keyList,
            servConn));
    // Send the last chunk (the only chunk for individual and list keys)
    // always send it back, even if the list is of zero size.
    sendRegisterInterestResponseChunk(region, regex, keyList, true, servConn);
  }
Process an interest request of type {@link InterestType#REGULAR_EXPRESSION}
geode-core/src/main/java/org/apache/geode/internal/cache/tier/sockets/BaseCommand.java