public function get(string $key): string
    {
        $key = $this->getKey($key);
        $value = $this->headers[$key] ?? "";
        return is_array($value) ? implode(", ", $value) : $value;
    }
public function get(string $key): string
    {
        $key = $this->getKey($key);
        $value = $this->headers[$key] ?? "";
        return is_array($value) ? implode(", ", $value) : $value;
    }
public function get ( string $ key ) : string { $ key = $ this -> getKey ( $ key ) ; $ value = $ this -> headers [ $ key ] ?? "" ; return is_array ( $ value ) ? implode ( ", " , $ value ) : $ value ; }
Get a header value

@param string $key
@return string
Get a header value