Runtime memory statistics

[Mark Ruys]

Is there a way to determine the current maximum heap usage. I want to check in 
my application how low free heap became so far to warn if it got too low. Idem 
for the stacks. Basically tools like 
https://os.mbed.com/docs/mbed-os/v5.14/tutorials/optimizing.html#runtime-memory-statistics
 
<https://os.mbed.com/docs/mbed-os/v5.14/tutorials/optimizing.html#runtime-memory-statistics>

Thanks,

Mark

PS This gives me the current free heap: 
    uint16_t heap_free = &__HeapLimit - (char *)_sbrk(0)
For stack I iterate os_task_info_get_next(), giving me oti_stksize and 
oti_stkusage.