Re: perfomance of set/hashset operation between python and nim

[def]

kcachegrind:
    
    
    nim -d:release --debugger:native c mydiff
    valgrind --tool=callgrind ./mydiff file1 file2
    kcachegrind callgrind.out.*
    

Also used here for example: 
[https://hookrace.net/blog/writing-an-async-logger-in-nim/#optimization](https://hookrace.net/blog/writing-an-async-logger-in-nim/#optimization)