GattlinkService()
Represents a Bluetooth GATT Link Service hosted on mobile that allows reliable streaming of arbitrary data over a BLE connection using the GATT protocol, with support for BLE/GATT stacks that don't always have the necessary support for writing GATT characteristics back-to-back without dropping data
Note: Fitbit has registered the new public FitbitGattlinkService to the bluetooth SIG. From now on, new trackers will host FitbitGattlinkService instead of GattlinkService