How to resume iteration from previous point in associative array

[Tarman]

@bearophile:

Thanks for your suggestion! Yes we've tried this but 
unfortunately the performance doesn't work for us, maybe because 
all our CPUs are quite saturated.

@simendsjo:

Thanks also for your suggestion, we are using tasks and yield in 
our code but in this case we felt that using it just to resume 
iteration was perhaps a misuse of the feature although we would 
be interested to see what the overhead is.

@Mr Pankrath:

Thanks that looks like what we need!