Field::addFetchDataModifier

public function addFetchDataModifier($modifier)
{
	// append only when not null. and when is null - delay it
	if ($this->fetchDataModifiers === null)
	{
		$this->additionalFetchDataModifiers[] = $modifier;
	}
	else
	{
		$this->appendFetchDataModifier($modifier);
	}

	return $this;
}