get_suffix example

    public function generate_filename( $suffix = null, $dest_path = null, $extension = null ) {
        // $suffix will be appended to the destination filename, just before the extension.         if ( ! $suffix ) {
            $suffix = $this->get_suffix();
        }

        $dir = pathinfo( $this->file, PATHINFO_DIRNAME );
        $ext = pathinfo( $this->file, PATHINFO_EXTENSION );

        $name    = wp_basename( $this->file, ".$ext" );
        $new_ext = strtolower( $extension ? $extension : $ext );

        if ( ! is_null( $dest_path ) ) {
            if ( ! wp_is_stream( $dest_path ) ) {
                $_dest_path = realpath( $dest_path );