code: private Stream<String> getKeysStream() {
          val cursor = client.getConnectionFactory().getConnection()
                  .scan(ScanOptions.scanOptions().match(getPatternTicketRedisKey())
                  .count(SCAN_COUNT)
                  .build());
          return StreamSupport
              .stream(Spliterators.spliteratorUnknownSize(cursor, Spliterator.ORDERED), false)
              .map(key -> (String) client.getKeySerializer().deserialize(key))
              .collect(Collectors.toSet())
              .stream()
              .onClose(() -> {
                  try {
                      cursor.close();
                  } catch (final IOException e) {
                      LOGGER.error("Could not close Redis connection", e);
                  }
              });
      }
docs: Get a stream of all CAS-related keys from Redis DB.
  
  @return stream of all CAS-related keys from Redis DB