parallel_with_rx.py

import time
import concurrent.futures
import rx

def return_slowly(i):
    time.sleep(1)
    return i

with concurrent.futures.ProcessPoolExecutor(5) as executor:
    rx.Observable.from_(range(5)).flat_map(
        lambda i: executor.submit(return_slowly, i)
    ).subscribe(print)
    
# $ time py3 parallel_with_rx.py
# 3
# 2
# 1
# 0
# 4
# 
# real    0m1.231s
# user    0m0.196s
# sys     0m0.057s

# how:
#
# 1. https://github.com/ReactiveX/RxPY/blob/09ed65003d2e579753b7d0c257c5f5ac318076d9/rx/linq/observable/selectmany.py#L12
# 2. https://github.com/ReactiveX/RxPY/blob/3e44b48f84f851ab37bbffdd4725d41d88061ef2/rx/linq/observable/fromfuture.py#L29
#