@ProgVal, could you try following?
I doubt that this difference just shows rlimit behavior, not memory usage.

---
$ cat rlimit_difference_linux_versions.py 
import sys
import queue
import multiprocessing
from urllib.request import Request, urlopen
import resource
import tracemalloc

def fetch():
    url = 'http://python.org/'
    request = Request(url)
    fd = urlopen(request)
    return 'ok'

fetch()
print(tracemalloc.get_traced_memory())

$ /usr/bin/time python3 rlimit_difference_linux_versions.py 
(0, 0)
0.12user 0.01system 0:01.47elapsed 9%CPU (0avgtext+0avgdata 18372maxresident)k
0inputs+0outputs (0major+2639minor)pagefaults 0swaps

$ PYTHONTRACEMALLOC=1 /usr/bin/time python3 rlimit_difference_linux_versions.py 
(6072093, 6140554)
0.22user 0.01system 0:01.52elapsed 15%CPU (0avgtext+0avgdata 22640maxresident)k
0inputs+0outputs (0major+3942minor)pagefaults 0swaps