The type crCOROUTINE_CODE is defined as a function that returns void and takes an CoRoutineHandle_t and an index as its parameters. All functions that
implement a co-routine should be of this type (demonstrated above).
Co-routines are created by calling xCoRoutineCreate().
Points to note:
All co-routine functions must start with a call to crSTART().
All co-routine functions must end with a call to crEND().
Co-routine functions should never return so are typically implemented as a continuous loop.
Many co-routines can be created from a single co-routine function. The uxIndex parameter is provided as a means of distinguishing between such