GroupSender::clearRedundantUserEvents

private function clearRedundantUserEvents(array $groupedByUser): array
{
	$result = [];

	foreach ($groupedByUser as $userId => $userEvents)
	{
		$groupedByUser[$userId] = current($userEvents);
	}

	$uniqueEvents = array_unique($groupedByUser);
	foreach ($uniqueEvents as $event)
	{
		$result[] = [
			'EVENT' => $event,
			'USER_IDS' => array_keys($groupedByUser, $event),
		];
	}

	return $result;
}