src/Soluble/Normalist/Synthetic/ResultSet/ResultSet.php
public function count()
    {
        if ($this->count === null) {
            $this->count = $this->dataSource->count();
        }
        return $this->count;
    }
public function count()
    {
        if ($this->count === null) {
            $this->count = $this->dataSource->count();
        }
        return $this->count;
    }
Countable: return count of rows

@return int