State::isPossibleState

private function isPossibleState($state)
{
	$possibleStates = $this->getPossibleStates();

	//TODO: remove
	if (!$this->letter->isSupportReiterate() && !$this->letter->isTrigger())
	{
		$possibleStates = array_filter($possibleStates, function ($value)
		{
			return  !in_array($value, [self::WAITING, self::HALTED]);
		});
	}

	return in_array($state, $possibleStates);
}