In Simulink allow to export S-Function Blocks that support to run as Co-Simulation on Multiple Cores

[traversaro]

As documented in https://it.mathworks.com/help/simulink/ug/run-co-simulation-components-on-multiple-cores.html, in Simulink it is possible to run the update of different blocks in different threads, if the block respect some conditions for which they can be consider Co-Simulation slaves, the requirements, listed in https://it.mathworks.com/help/simulink/ug/run-co-simulation-components-on-multiple-cores.html under "S-Function Block Limitations", are:

• Must have a single rate — ssSetSampleTime(SimStruct *S, int_T st_index, time_T period) must be called to register only one discrete rate.
• Must have a fixed sample time — In time_T ssSetSampleTime(SimStruct *S, int_T st_index, time_T period), period cannot be VARIABLE_SAMPLE_TIME.
• Cannot have continuous states — In ssSetNumContStates(SimStruct *S, int_T n), n must be 0
• Must have no direct feedthrough ports — In ssSetInputPortDirectFeedThrough(SimStruct *S, int_T port, int_T dirFeed), dirFeed must be 0 for each input port.
• Must be thread safe — In ssSetRuntimeThreadSafetyCompliance(SimStruct *S, int_T val), val must be RUNTIME_THREAD_SAFETY_COMPLIANCE_TRUE.
• Must be exception-free — In ssSetOptions(SimStruct *S, uint_T options), options must include SS_OPTION_EXCEPTION_FREE_CODE.

Some of them are not dictated by BlockFactory itself, so we should find a way to be configurable from the developer develoing BlockFactory blocks. Furthermore, this mode seems to support natively FMI, so an alternative way to achieve this could be to work on #5 .

[traversaro]

The simulation runs on a single thread for accelerator and rapid accelerator modes.

If I understood correctly this sentence in https://it.mathworks.com/help/simulink/ug/run-co-simulation-components-on-multiple-cores.html, this may mean that #53 is a prerequisite for this.