code: public static void resetOnEachOperator(String key) {
  		Objects.requireNonNull(key, "key");
  		log.debug("Reset onEachOperator: {}", key);
  
  		synchronized (log) {
  			onEachOperatorHooks.remove(key);
  			onEachOperatorHook = createOrUpdateOpHook(onEachOperatorHooks.values());
  		}
  	}
docs: Remove the sub-hook with key {@code key} from the onEachOperator hook. No-op if
  no such key has been registered, and equivalent to calling {@link #resetOnEachOperator()}
  if it was the last sub-hook.
  
  @param key the key of the sub-hook to remove