Public Interface IActivityActions
    ''' <summary>
    ''' The employee starts the activity.
    ''' </summary>
    ''' <param name="employee"></param>
    Sub StartActivity(employee As IEmployee)

    ''' <summary>
    ''' The employee stops the activity.
    ''' </summary>
    Sub StopActivity()

    ''' <summary>
    ''' The employee finishes the activity.
    ''' </summary>
    Sub FinishActivity()
End Interface