src/StringBuilder.php
public function append($string)
    {
        $string = static::convertString($string, $this->encoding);

        $this->string .= $string;

        return $this;
    }
public function append($string)
    {
        $string = static::convertString($string, $this->encoding);

        $this->string .= $string;

        return $this;
    }
Append a string to the sequence.

@param string $string The sequence to append.

@return StringBuilder