如何打开CSV文件并使用WordPress WP_Filesystem编写内容

Question

最近，我制作了一个WordPress插件，并在其中提供了导出到csv的功能。我使用了php默认的fopen，fclose，它可以正常工作。但是，当我使用envato主题检查器检查插件时，建议您使用WP_Filesystem方法。但是我找不到打开csv文件并关闭而不保存到上载目录的方法。

if(isset($_POST['download_csv'])):
        $filename = 'emails-' . time() . '.csv';
        $header_row = array( 0 => 'Email', 1 => 'Date' );
        $data_rows = array();
        $users = $this->get_emails();
        foreach( $users as $u ):
            $row = array();
            $row[0] = $u->email;
            $row[1] = $u->dateTime;
            $data_rows[] = $row;
        endforeach;
        header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
        header('Content-Description: File Transfer');
        header("Content-type: text/csv");
        header("Content-Disposition: attachment; filename={$filename}");
        header("Expires: 0");
        header("Pragma: public");
        $fh = @fopen( 'php://output', 'w' );
        $headerDisplayed = false;
        foreach( $data_rows as $data ):
            if( !$headerDisplayed ):
                fputcsv($fh, $header_row);
                $headerDisplayed = true;
            <?php   endif;
            fputcsv($fh, $data);
        endforeach;
        fclose($fh);
        exit;
    endif;
?>

if(isset($_POST['download_csv'])): $filename = 'emails-' . time() . '.csv'; $header_row = array( 0 => 'Email', 1 => 'Date' ); $data_rows = array(); $users = $this->get_emails(); foreach( $users as $u ): $row = array(); $row[0] = $u->email; $row[1] = $u->dateTime; $data_rows[] = $row; endforeach; header("Cache-Control: must-revalidate, post-check=0, pre-check=0"); header('Content-Description: File Transfer'); header("Content-type: text/csv"); header("Content-Disposition: attachment; filename={$filename}"); header("Expires: 0"); header("Pragma: public"); $fh = @fopen( 'php://output', 'w' ); $headerDisplayed = false; foreach( $data_rows as $data ): if( !$headerDisplayed ): fputcsv($fh, $header_row); $headerDisplayed = true; <?php endif; fputcsv($fh, $data); endforeach; fclose($fh); exit; endif; ?>

一切正常。但是知道如何将其与WP_Filesystem集成吗？