Multithreaded user application 'exampleB21':
  - title        : XMTGuiAppMessaging - RC
  - location     : ~/xcofdk/tests/xuserapp/basic/xmt/rc/exampleB21/
  - description  : This Tk application uses a synchronous main task and multiple asynchronous service tasks.
                   It demostrates general use of multiple tasks.
  - remark(s)    : a) The application is made quite parameterized to serve as 'generic application'
                      used by other examples wherever applicable.
                   b) It also is used to highlight basic features of the subsystem messaging.
                   c) This example uses rapid construction (RC) approach to create application tasks.
