Custom Response facade for additional response types in Laravel 4

Response.php

<?php namespace Acme\Extensions\Facades;

class Response extends \Illuminate\Support\Facades\Response
{
    public static function csv($data, $filename = 'data.csv', $status = 200, $delimiter = "|", $linebreak = "\n", $headers = array())
    {
        return static::stream(function () use ($data, $delimiter, $linebreak) {

            foreach ($data as $row) {
                $keys = array(); $values = array();
                $i = (isset($i)) ? $i+1 : 0;
                foreach ($row as $k => $v) {
                    if (!$i) $keys[] = is_string($k) ? '"' . str_replace('"', '""', $k) . '"' : $k;
                    $values[] = is_string($v) ? '"' . str_replace('"', '""', $v) . '"' : $v;
                }
                if (count($keys) > 0) echo implode($delimiter, $keys) . $linebreak;
                if (count($values) > 0) echo implode($delimiter, $values) . $linebreak;
            }

        }, 200, array_merge(array(
            'Content-type' => 'application/csv',
            'Cache-Control' => 'must-revalidate, post-check=0, pre-check=0',
            'Content-Description' => 'File Transfer',
            'Content-type' => 'text/csv',
            'Content-Disposition' => 'attachment; filename=' . $filename,
            'Expires' => '0',
            'Pragma' => 'public',
        ), $headers));
    }
}