iOS BLE- Does Apple support Extended Advertising or not?

I'm trying to broadcast some customized data into the peripheral advertisingData package. Based on the WWDC 2019, and some posts Ios BLE extended Advertising example, seems like with iphone devices that support bluetooth 5.0, we can send up to 124 bytes.

However Apple didn't say how to send extensive advertisement data (which key or API to use). And I tested with the CBAdvertisementDataLocalNameKey, seems like I can still ONLY send within 31 bytes. My code:

@IBAction func switchChanged(_ sender: Any) {
    // All we advertise is our service's UUID.
    if advertisingSwitch.isOn {
         peripheralManager.startAdvertising([CBAdvertisementDataServiceUUIDsKey: [TransferService.serviceUUID], CBAdvertisementDataLocalNameKey: "1234567890asddsgsfhgfshfgshfsggdrfgdbfsbfgshgfshbfgb"])
    } else {
        peripheralManager.stopAdvertising()
    }
}

And on the central side, my code:

func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String: Any], rssi RSSI: NSNumber) {
    if let name = advertisementData[CBAdvertisementDataLocalNameKey] as? String {
    os_log("name:", String(name))
    }
}

But I only got the first some bytes: name String "1234567890asddsgsfhgfshfgs"

My question is, does apple really support Extended Advertising starting from iPhone 8? If so, how should I use it to send data up to 124 bytes?