src/Debug/Utf8.php
public static function toUtf8($str)
    {
        if (\extension_loaded('mbstring') && \function_exists('iconv')) {
            $encoding = \mb_detect_encoding($str, \mb_detect_order(), true);
            if (!$encoding) {
                $str_conv = false;
                if (\function_exists('iconv')) {
                    $str_conv = \iconv('cp1252', 'UTF-8', $str);
                }
                if ($str_conv === false) {
                    $str_conv = \htmlentities($str, ENT_COMPAT);
                    $str_conv = \html_entity_decode($str_conv, ENT_COMPAT, 'UTF-8');
                }
                $str = $str_conv;
            } elseif (!\in_array($encoding, array('ASCII','UTF-8'))) {
                $str_new = \iconv($encoding, 'UTF-8', $str);
                if ($str_new !== false) {
                    $str = $str_new;
                }
            }
        }
        return $str;
    }
public static function toUtf8($str)
    {
        if (\extension_loaded('mbstring') && \function_exists('iconv')) {
            $encoding = \mb_detect_encoding($str, \mb_detect_order(), true);
            if (!$encoding) {
                $str_conv = false;
                if (\function_exists('iconv')) {
                    $str_conv = \iconv('cp1252', 'UTF-8', $str);
                }
                if ($str_conv === false) {
                    $str_conv = \htmlentities($str, ENT_COMPAT);
                    $str_conv = \html_entity_decode($str_conv, ENT_COMPAT, 'UTF-8');
                }
                $str = $str_conv;
            } elseif (!\in_array($encoding, array('ASCII','UTF-8'))) {
                $str_new = \iconv($encoding, 'UTF-8', $str);
                if ($str_new !== false) {
                    $str = $str_new;
                }
            }
        }
        return $str;
    }
Attempt to convert string to UTF-8 encoding

@param string $str string to convert

@return string