[MPI] Communication failure between workers

[Retribution98]

Reproducer:

import unidist
import time


@unidist.remote
def sleep(seconds):
    time.sleep(seconds)


@unidist.remote
def f(arr):
    unidist.get(sleep.remote(0.2))
    return sum(arr)


def g():
    obj_ref = unidist.put(100)
    arr = [obj_ref]
    for i in range(22):
        arr.append(f.remote(arr))
        time.sleep(0.1)
    return f.remote(arr)


unidist.init()

results = []
for i in range(5):
    results.append(g())

print(unidist.get(results))