src/Khayyam/Khayyam.php
public function diffInSeconds(Carbon $dt = null, $abs = true)
    {
        $dt = ($dt === null) ? static::now($this->tz) : $dt;
        $value = $dt->getTimestamp() - $this->getTimestamp();

        return $abs ? abs($value) : $value;
    }
public function diffInSeconds(Carbon $dt = null, $abs = true)
    {
        $dt = ($dt === null) ? static::now($this->tz) : $dt;
        $value = $dt->getTimestamp() - $this->getTimestamp();

        return $abs ? abs($value) : $value;
    }
Get the difference in seconds

@param Carbon  $dt
@param boolean $abs Get the absolute of the difference

@return integer