FitbitGattlinkService()
Represents the Gattlink 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
Fitbit has registered the Gattlink Service to SIG with 16-bit UUID 0xFD62, which has a different service UUID from original one. https://www.bluetooth.com/specifications/assigned-numbers/16-bit-uuids-for-members/