[RLlib] Removed config["sample_async"] restriction for A3C-torch. (#8617)

rllib/agents/a3c/a3c.py

@@ -54,11 +54,6 @@ def get_policy_class(config):
 def validate_config(config):
     if config["entropy_coeff"] < 0:
         raise DeprecationWarning("entropy_coeff must be >= 0")
-    if config["sample_async"] and config["use_pytorch"]:
-        config["sample_async"] = False
-        logger.warning(
-            "The sample_async option is not supported with use_pytorch: "
-            "Multithreading can be lead to crashes if used with pytorch.")
 
 
 def execution_plan(workers, config):