Ajax::ajaxDownloadReport()

	public function ajaxDownloadReport()
	{
		$hash    = bp_ld_sync()->getRequest('hash');
		$exports = get_transient($hash);
		$info    = get_transient("{$hash}_info");

        if (! $hash || ! $exports) {
            wp_die(__('Session has expired, please refresh and try again.', 'buddyboss'));
        }

		$file = fopen('php://output', 'w');
    	fputcsv($file, wp_list_pluck($info['columns'], 'label'));

    	foreach ($exports as $export) {
    		fputcsv($file, $export);
    	}

		header('Content-Encoding: '. DB_CHARSET);
		header('Content-type: text/csv; charset='.DB_CHARSET);
		header('Content-Disposition: attachment; filename='. $info['filename']);
		header('Pragma: no-cache');
		header('Expires: 0');
    	fclose($df);
	    die();
	}