* usually include:
 *
 * <ul>
 *   <li>Static methods named {@code of}, accepting an explicit list of elements or entries.
 *   <li>Static methods named {@code copyOf} (or {@code copyOfSorted}), accepting an existing
 *       collection whose contents should be copied.
 *   <li>A static nested {@code Builder} class which can be used to populate a new immutable
 *       instance.
 * </ul>
 *
 * <h4>Warnings</h4>
 *

 * the graph), you should use the non-mutating {@link ValueGraph} interface, or an {@link
 * ImmutableValueGraph}.
 *
 * <p>You can create an immutable copy of an existing {@code ValueGraph} using {@link
 * ImmutableValueGraph#copyOf(ValueGraph)}:
 *
 * <pre>{@code
 * ImmutableValueGraph<Integer, Double> immutableGraph = ImmutableValueGraph.copyOf(graph);
 * }</pre>
 *

	h.status.Store(statusClosed)
	h.storeCtxCancel()

	// Wait for messages to be sent...
	h.wg.Wait()

	// Set logch to nil and close it.
	// This will block all Send operations,
	// and finish the existing ones.
	// All future ones will be discarded.
	h.logChMu.Lock()
	xioutil.SafeClose(h.logCh)
	h.logCh = nil
	h.logChMu.Unlock()

			objs:       []runtime.Object{kubeSystemNamespace, sa2, saSecret, saSecret2},
			secretName: saSecret.Name,
			name:       "cluster-foo",
			want:       "cal-want",
		},
		{
			testName:        "fail when non-existing secret name provided",
			objs:            []runtime.Object{kubeSystemNamespace, sa2, saSecret, saSecret2},
			secretName:      "nonexistingSecret",
			name:            "cluster-foo",
			want:            "cal-want",

		h.ID, _ = h.disk.GetDiskID()
		h.PoolIndex, h.SetIndex, h.DiskIndex = h.disk.GetDiskLoc()
	}
	h.mu.Unlock()
	return h.save(ctx)
}

// save will unconditionally save the tracker and will be created if not existing.
func (h *healingTracker) save(ctx context.Context) error {
	h.mu.Lock()
	if h.PoolIndex < 0 || h.SetIndex < 0 || h.DiskIndex < 0 {
		// Attempt to get location.
		if api := newObjectLayerFn(); api != nil {

 * href="http://en.wikipedia.org/wiki/Null_Object_pattern">null object</a> for the type in question.
 *
 * <p>This class is not intended as a direct analogue of any existing "option" or "maybe" construct
 * from other programming environments, though it may bear some similarities.
 *
 * <p>An instance of this class is serializable if its reference is absent or is a serializable
 * object.
 *

                if ( log.isTraceEnabled() ) {
                    log.trace("Reusing existing session " + ssn);
                }
                return ssn.acquire();
            }
            else if ( log.isTraceEnabled() ) {
                log.trace("Existing session " + ssn + " does not match " + tf.getCredentials());
            }
        }

        /* logoff old sessions */

            if (!properties.containsKey(key)) {
                this.remove(key);
                modified = true;
            }
        }
        // Update existing keys
        for (String key : properties.keySet()) {
            String v = this.get(key);
            List<String> comments = properties.getComments(key);
            List<String> value = properties.getRaw(key);

			diffSlc := getMissingSiteNames(currDeploymentIDsSet, deploymentIDsSet, currSites.Sites)
			return madmin.ReplicateAddStatus{}, errSRInvalidRequest(fmt.Errorf("all existing replicated sites must be specified - missing %s", strings.Join(diffSlc, " ")))
		}
	}

	// validate that all clusters are using the same IDP settings.
	err = c.validateIDPSettings(ctx, sites)
	if err != nil {

	if b.Created.IsZero() {
		configs, err := b.getAllLegacyConfigs(ctx, objectAPI)
		if err != nil {
			return b, err
		}

		if len(configs) > 0 {
			// Old bucket without bucket metadata. Hence we migrate existing settings.
			if err = b.convertLegacyConfigs(ctx, objectAPI, configs); err != nil {
				return b, err
			}
		}
	}

	if parse {
		// nothing to update, parse and proceed.