@Override
    public void run() {
      Transition edge;
      while (true) {
        try {
          edge = edges.take();
          if (edge instanceof FlushToken) {
            ((FlushToken) edge).cdl.countDown();
            continue;
          }

          if (appender != null) {
            appender.write(edge);
          }
        } catch (InterruptedException e) {
          // do nothing
        } catch (Throwable t) {
          t.printStackTrace();
          appender.close();
          appender = null;
        }
      }
    }
Should be invoked when GemFire cache is closing or closed.
geode-core/src/main/java/org/apache/geode/internal/sequencelog/SequenceLoggerImpl.java