Repeater - Array to String Conversion when save - logImplodeAssoc

protected $casts = ['urls' => 'json'];

 /**
     * Format an assoc array as a key/value string for logging
     * @return string
     */

    public static function logImplodeAssoc(array $attrs): string {
        $l = '';
        foreach( $attrs as $k => $v ) {
          **  $l .= "{ $k => $v } ";**
        }
        return $l;
    }

 Repeater::make('urls')->schema([
                        TextInput::make('Stream-URL')
                    ])
                    ->hidden(function(Get $get){
                        if(!in_array($get('type'),[9,7,11,10])){
                            return true;
                        }
                        return false;
                    }),

  TextColumn::make('outstream.urls')->state(function(Model $record){
                    $out = '';
                    foreach((array)$record->outipstream->urls as $url){
                        $out .= $url['Stream-URL'].' ';
                    }
                    return $out;
                }),