protected function extractTimestamp($record = []) {
        return isset($record[$this->timestampKey]) ? $record[$this->timestampKey] : null;
    }
protected function extractTimestamp($record = []) {
        return isset($record[$this->timestampKey]) ? $record[$this->timestampKey] : null;
    }
protected function extractTimestamp ( $ record = [ ] ) { return isset ( $ record [ $ this -> timestampKey ] ) ? $ record [ $ this -> timestampKey ] : null ; }
Extract session timestamp from record
@param array $record
@return integer|null
Extract session timestamp from record