@Override
    public boolean onUnbind(final Intent intent) {
        // After using a given device, you should make sure that BluetoothGatt.close() is called
        // such that resources are cleaned up properly.  In this particular example, close() is
        // invoked when the UI is disconnected from the Service.
        close();
        return super.onUnbind(intent);
    }
Initializes a reference to the local Bluetooth adapter.

@return Return true if the initialization is successful.
sample_app/src/main/java/uk/co/alt236/btlescan/services/BluetoothLeService.java