/**
* Checks for valid preconditions.
*
* @param MultiBulk $iterator Inner multibulk response iterator.
*/
protected function checkPreconditions(MultiBulk $iterator)
{
if ($iterator->getPosition() !== 0) {
throw new InvalidArgumentException('Cannot initialize a tuple iterator using an already initiated iterator.');
}
if (($size = count($iterator)) % 2 !== 0) {
throw new UnexpectedValueException("Invalid response size for a tuple iterator.");
}
}
