### Async Context Manager { #async-context-manager }

If you check, the function is decorated with an `@asynccontextmanager`.

That converts the function into something called an "**async context manager**".

{* ../../docs_src/events/tutorial003.py hl[1,13] *}

.28.7](https://console.cloud.google.com/gcr/images/k8s-artifacts-prod/us/kube-controller-manager) | [amd64](https://console.cloud.google.com/gcr/images/k8s-artifacts-prod/us/kube-controller-manager-amd64), [arm64](https://console.cloud.google.com/gcr/images/k8s-artifacts-prod/us/kube-controller-manager-arm64), [ppc64le](https://console.cloud.google.com/gcr/images/k8s-artifacts-prod/us/kube-controller-manager-ppc64le), [s390x](https://console.cloud.google.com/gcr/images/k8s-artifacts-prod/us/kube...

    private final ChannelManager manager;
    private final ExecutorService executor;
    private final ConcurrentMap<String, FailoverState> failoverStates;

    /**
     * Create channel failover handler
     *
     * @param manager channel manager
     */
    public ChannelFailover(ChannelManager manager) {
        this.manager = manager;
        this.executor = Executors.newCachedThreadPool(r -> {

            public String getQueryBrowserLangParameterName() {
                return "lang";
            }
        };
        ComponentUtil.setFessConfig(mockConfig);

        // Setup mock request manager
        RequestManager mockRequestManager = createMockRequestManager("en_US");

        // Execute
        OptionalThing<Locale> result = provider.findBusinessLocale(null, mockRequestManager);

        // Verify

        private final String resourceId;
        private final ResourceManager manager;
        private volatile boolean closed = false;

        ManagedResource(T resource, String resourceId, ResourceManager manager) {
            this.resource = resource;
            this.resourceId = resourceId;
            this.manager = manager;
        }

        public T get() {
            if (closed) {

		CheckUser(t, user, users2[idx])
		if users2[idx].Manager == nil {
			t.Fatalf("Failed to load Manager")
		}
		// manager
		CheckUser(t, *user.Manager, *users2[idx].Manager)
		// user pet
		if users2[idx].NamedPet == nil {
			t.Fatalf("Failed to load NamedPet")
		}
		CheckPet(t, *user.NamedPet, *users2[idx].NamedPet)
		// manager pet
		if users2[idx].Manager.NamedPet == nil {
			t.Fatalf("Failed to load NamedPet")

    }
    
    public ChannelLoadBalancer(ChannelManager manager) {
        this.manager = manager;
        this.strategy = LoadBalancingStrategy.ADAPTIVE;
    }
    
    public ChannelInfo selectChannel(SMBMessage message) {
        Collection<ChannelInfo> availableChannels = manager.getHealthyChannels();
        
        if (availableChannels.isEmpty()) {

    /**
     * Create a new handle reconnector
     * @param manager the persistent handle manager
     */
    public HandleReconnector(PersistentHandleManager manager) {
        this(manager, 3, 1000);
    }

    /**
     * Create a new handle reconnector with custom settings
     * @param manager the persistent handle manager
     * @param maxRetries maximum number of retry attempts

        GSSManager manager = GSSManager.getInstance();
        GSSCredential clientCreds = null;
        Oid mechOid = JGSS_KRB5_MECH_OID;
        if (realm != null) {
            this.serviceName = manager.createName(service + "/" + host + "@" + realm, JGSS_KRB5_NAME_OID, mechOid);
        } else {
            this.serviceName = manager.createName(service + "@" + host, GSSName.NT_HOSTBASED_SERVICE, mechOid);

	users := []User{
		{
			Name: "TestMergeNestedPreloadWithNestedJoin-1",
			Manager: &User{
				Name: "Alexis Manager",
				Tools: []Tools{
					{Name: "Alexis Tool 1"},
					{Name: "Alexis Tool 2"},
				},
			},
		},
		{
			Name: "TestMergeNestedPreloadWithNestedJoin-2",
			Manager: &User{
				Name: "Jinzhu Manager",
				Tools: []Tools{
					{Name: "Jinzhu Tool 1"},
					{Name: "Jinzhu Tool 2"},