Suspends the scheduler without disabling interrupts. Context switches will not
occur while the scheduler is suspended. RTOS ticks that occur while the scheduler
is suspended will be held pending until the scheduler has been unsuspended using
a call to xTaskResumeAll().
API functions that have the potential to cause a context switch (for example, vTaskDelayUntil(), xQueueSend(), etc.) must not be called while the
scheduler is suspended.
// At some point the task wants to perform a long operation during
// which it does not want to get swapped out. It cannot use
// taskENTER_CRITICAL ()/taskEXIT_CRITICAL () as the length of the
// operation may cause interrupts to be missed - including the
// Prevent the RTOS kernel swapping out the task.
// Perform the operation here. There is no need to use critical
// sections as we have all the microcontroller processing time.
// During this time interrupts will still operate and the RTOS kernel
// tick count will be maintained.
// The operation is complete. Restart the RTOS kernel.