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 CLIENT-SERVER COMMUNICATION PATTERN
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A periodic client thread calls subprograms 
provided by a sporadic server thread.

The functional behavior of the client thread is specified by a 
standard Behavior_Specification subclause. 
It calls two remote subprograms in sequence and synchronizes with 
the server according to the specified protocol:
- ASER: no synchronization; standard scheduling rules apply.
- LSER: ensures that input parameters are frozen on server side 
before letting the client continue its execution.
- HSER: the clients waits for complete execution of the remote 
service before continuing.

Know issues:
- LSER mode is not supported yet.
- parameters passing to remote subprograms does not work yet