src/I18n/Formatter.php
public function asEmail($value, $options = [], $encoding = null)
    {
        if ($value === null) {
            return $this->nullDisplay;
        }

        return Html::mailto(Html::encode($value, true, $encoding), $value, $options);
    }
public function asEmail($value, $options = [], $encoding = null)
    {
        if ($value === null) {
            return $this->nullDisplay;
        }

        return Html::mailto(Html::encode($value, true, $encoding), $value, $options);
    }
Formats the value as a mailto link.
@param string $value the value to be formatted.
@param array  $options the tag options in terms of name-value pairs. See [[Html::mailto()]].
@param string $encoding
@return string the formatted result.