Xamarin LinkOS Bluetooth connection not closed

Hi, I am using LinkOS SDK on Xamarin by following this tutorial:

Basic Xamarin Print Example

The printing is working, but the bluetooth connection is not closed after printing. As a result, another phone cannot connect to the printer until I manually turn off bluetooth on Android or iOS.

 

I did call the connection.close() method:

finally
{
     if (connection.IsConnected)
          connection.Close();
}

 

How should I close it?