func (c *Client) Close() {
	atomic.StoreInt32(&c.connected, closed)
}

// NewClient - returns new REST client.
func NewClient(uu *url.URL, tr http.RoundTripper, auth func() string) *Client {
	connected := int32(online)
	urlStr := uu.String()
	u, err := url.Parse(urlStr)
	if err != nil {
		// Mark offline, with no reconnection attempts.
		connected = int32(offline)
		err = &url.Error{URL: urlStr, Err: err}
	}

    assertTrue(Range.closed(3, 5).isConnected(Range.open(5, 6)));
    assertTrue(Range.closed(3, 5).isConnected(Range.closed(5, 6)));
    assertTrue(Range.closed(5, 6).isConnected(Range.closed(3, 5)));
    assertTrue(Range.closed(3, 5).isConnected(Range.openClosed(5, 5)));
    assertTrue(Range.open(3, 5).isConnected(Range.closed(5, 6)));
    assertTrue(Range.closed(3, 7).isConnected(Range.open(6, 8)));

    }

    public void addOnConnectListener(final OnConnectListener listener) {
        onConnectListenerList.add(listener);
    }

    public boolean connected() {
        return connected;
    }

    public void connect() {
        destroy();
        client = createClient();

        final ClusterHealthResponse healthResponse =

   *
   * <p>For example,
   *
   * <ul>
   *   <li>{@code [2, 4)} and {@code [5, 7)} are not connected
   *   <li>{@code [2, 4)} and {@code [3, 5)} are connected, because both enclose {@code [3, 4)}
   *   <li>{@code [2, 4)} and {@code [4, 6)} are connected, because both enclose the empty range
   *       {@code [4, 4)}
   * </ul>
   *

   *
   * <p>For example,
   *
   * <ul>
   *   <li>{@code [2, 4)} and {@code [5, 7)} are not connected
   *   <li>{@code [2, 4)} and {@code [3, 5)} are connected, because both enclose {@code [3, 4)}
   *   <li>{@code [2, 4)} and {@code [4, 6)} are connected, because both enclose the empty range
   *       {@code [4, 4)}
   * </ul>
   *

)

type logger = func(ctx context.Context, err error, id string, errKind ...interface{})

// ErrNotConnected - indicates that the target connection is not active.
var ErrNotConnected = errors.New("not connected to target server/service")

// Target - store target interface
type Target interface {
	Name() string
	SendFromStore(key Key) error
}

// Store - Used to persist items.
type Store[I any] interface {

	// of this function is to know if the "drive" has "format.json" or not
	// if it has a "format.json" then is it correct "format.json" or not.
	IsOnline() bool

	// Returns the last time this disk (re)-connected
	LastConn() time.Time

	// Indicates if disk is local or not.
	IsLocal() bool

	// Returns hostname if disk is remote.
	Hostname() string

	// Returns the entire endpoint.
	Endpoint() Endpoint

    assertEquals(
        ImmutableMap.of(Range.closedOpen(0, 1), 1, Range.closedOpen(1, 2), 1),
        rangeMap.asMapOfRanges());

    rangeMap.putCoalescing(Range.closedOpen(1, 1), 1); // empty range coalesces connected ranges
    assertEquals(ImmutableMap.of(Range.closedOpen(0, 2), 1), rangeMap.asMapOfRanges());
  }

  public void testPutCoalescingSubmapEmpty() {
    RangeMap<Integer, Integer> rangeMap = TreeRangeMap.create();

So, we declare the event handler function with standard `def` instead of `async def`.

///

### `startup` and `shutdown` together

There's a high chance that the logic for your *startup* and *shutdown* is connected, you might want to start something and then finish it, acquire a resource and then release it, etc.

	if err := target.init(); err != nil {
		return false, err
	}
	return target.isActive()
}

// errNotConnected - indicates that the target connection is not active.
var errNotConnected = errors.New("not connected to target server/service")

func (target *WebhookTarget) isActive() (bool, error) {
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()