system/I18n/TimeDifference.php
public function getSeconds(bool $raw = false)
	{
		if ($raw)
		{
			return $this->difference;
		}

		$time = clone($this->currentTime);
		return $time->fieldDifference($this->testTime, IntlCalendar::FIELD_SECOND);
	}
public function getSeconds(bool $raw = false)
	{
		if ($raw)
		{
			return $this->difference;
		}

		$time = clone($this->currentTime);
		return $time->fieldDifference($this->testTime, IntlCalendar::FIELD_SECOND);
	}
Returns the number of seconds difference between the two dates.

@param boolean $raw

@return integer