sys.Lock()
	for _, bucket := range buckets {
		sys.group.Forget(bucket)
		delete(sys.metadataMap, bucket)
		globalBucketMonitor.DeleteBucket(bucket)
	}
	sys.Unlock()
}

// RemoveStaleBuckets removes all stale buckets in memory that are not on disk.
func (sys *BucketMetadataSys) RemoveStaleBuckets(diskBuckets set.StringSet) {
	sys.Lock()
	defer sys.Unlock()

	for bucket := range sys.metadataMap {

				sys.hMutex.Unlock()
			}
			hcTimer.Reset(defaultHealthCheckDuration)
		case <-ctx.Done():
			return
		}
	}
}

// periodically rebuild the healthCheck map from list of targets to clear
// out stale endpoints
func (sys *BucketTargetSys) reloadHealthCheckers(ctx context.Context) {
	m := make(map[string]epHealth)
	tgts := sys.ListTargets(ctx, "", "")
	sys.hMutex.Lock()
	for _, t := range tgts {

			// initial server startup, however, it is needed for the case where
			// the STS account's policy mapping (for example in LDAP mode) may
			// be changed and the user's policy mapping in memory is stale
			// (because the policy change notification was missed by the current
			// server).
			//
			// The "policy not found" error is ignored because the STS account may

## Retrying Requests

Sometimes connections fail: either a pooled connection was stale and disconnected, or the webserver itself couldn’t be reached. OkHttp will retry the request with a different route if one is available.

## [Calls](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-call/)

If there's a problem with the connection, OkHttp will select another route and try again. This allows OkHttp to recover when a subset of a server's addresses are unreachable. It's also useful when a pooled connection is stale or if the attempted TLS version is unsupported.

   *
   * This method returns false unless it is overridden by a subclass.
   *
   * By default OkHttp will attempt to retransmit request bodies when the original request fails
   * due to any of:
   *
   *  * A stale connection. The request was made on a reused connection and that reused connection
   *    has since been closed by the server.
   *  * A client timeout (HTTP 408).

        .header("Cache-Control", "max-stale=180")
        .build()
    val response = client.newCall(request).execute()
    assertThat(response.body.string()).isEqualTo("A")
    assertThat(response.header("Warning")).isEqualTo(
      "110 HttpURLConnection \"Response is stale\"",
    )
  }

  @Test
  fun requestMaxStaleDirectiveWithNoValue() {
    // Add a stale response to the cache.
    server.enqueue(

   * implementation; otherwise refreshes will be performed during unrelated cache read and write
   * operations.
   *
   * <p>Currently automatic refreshes are performed when the first stale request for an entry
   * occurs. The request triggering refresh will make a synchronous call to {@link
   * CacheLoader#reload}
   * to obtain a future of the new value. If the returned future is already complete, it is returned

                final long deletedDocCount = deleteOldDocuments(searchEngineClient, docList);
                if (logger.isDebugEnabled()) {
                    logger.debug("Deleted {} stale documents", deletedDocCount);
                }
                final BulkResponse response =
                        searchEngineClient.addAll(fessConfig.getIndexDocumentUpdateIndex(), docList, (doc, builder) -> {

  // TODO GET preferred order - with tests to confirm this
  // 1. successful fresh cached GET response
  // 2. unsuccessful (404, 500) fresh cached GET response
  // 3. successful network response
  // 4. successful stale cached GET response
  // 5. unsuccessful response
  @Test
  fun usesCache() {
    val cache = Cache(cacheFs, "cache".toPath(), (100 * 1024).toLong())