code: public void simulateGattConnectionChange(int status, int newState) {
      for (BluetoothGatt bluetoothGatt : bluetoothGatts) {
        ShadowBluetoothGatt shadowBluetoothGatt = Shadow.extract(bluetoothGatt);
        BluetoothGattCallback gattCallback = shadowBluetoothGatt.getGattCallback();
        gattCallback.onConnectionStateChange(bluetoothGatt, status, newState);
      }
    }
docs: Causes {@link BluetoothGattCallback#onConnectionStateChange to be called for every GATT client.
  @param status Status of the GATT operation
  @param newState The new state of the GATT profile