Stream::getMetadata( $key = null ): mixed

215    public function getMetadata($key = null)216    {217        if (null !== $key && !\is_string($key)) {218            throw new \InvalidArgumentException('Metadata key must be a string');219        }220        if (!isset($this->stream)) {221            return $key ? null : [];222        }223        $meta = \stream_get_meta_data($this->stream);224        if (null === $key) {225            return $meta;226        }227        return $meta[$key] ?? null;228    }