public function concat($string): self
    {
        Assert::typeOf(['string', __CLASS__], $string);

        return new static($this->data . $string, $this->encoding);
    }
public function concat($string): self
    {
        Assert::typeOf(['string', __CLASS__], $string);

        return new static($this->data . $string, $this->encoding);
    }
public function concat ( $ string ) : self { Assert :: typeOf ( [ 'string' , __CLASS__ ] , $ string ) ; return new static ( $ this -> data . $ string , $ this -> encoding ) ; }
Concatenates given string to the end of this string

@param static|string $string
@return static
@throws InvalidArgumentException
@throws TypeError
Concatenates given string to the end of this string