void assertInitialized() {
    if (archiver == null && !config.getArchiveFileName().getPath().equals("")) {
      throw new IllegalStateException("This " + this + " was not initialized");
    }
  }
Closes any {@link StatArchiveWriter} currently in use by this handler.
geode-core/src/main/java/org/apache/geode/internal/statistics/StatArchiveHandler.java