There's a method called requestDataSending you could call right in a report's setup to get data into a datastore and retrieve it like this:

    function setup()
    {
        $this->src("pdo")
        ->pipe(...)
        ->pipe($this->dataStore("myds"))
        ->requestDataSending(); // this method populates data in datastore right at once
        $data = $this->dataStore("myds")->data(); // get data from the populated datastore
        // use $data for your purpose

Let us know if we understand your question correctly. Rgds,