[BugFix] Robust sync for non_blocking=True #1167

Job	Run time
unittests-atari-dqn	0s
unittests-d4rl	0s
unittests-gendgrl	0s
unittests-envpool	0s
unittests-minari	0s
unittests-openx	0s
unittests-roboset	0s
unittests-smacv2	0s
unittests-vd4rl	0s
unittests-pettingzoo / linux-job	9m 15s
unittests-gym (3.9, 12.1) / linux-job	18m 51s
unittests-brax (3.9, 12.1) / linux-job	8m 49s
unittests-robohive (3.9, 12.1) / linux-job	9m 9s
unittests-jumanji (3.9, 12.1) / linux-job	8m 48s
unittests-sklearn (3.9, 12.1) / linux-job	5m 46s
unittests-vmas (3.9, 12.1) / linux-job	11m 39s
	1h 12m 17s

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