protected function getStreamsArray()
    {
        $content = Psr7\stream_for();
        $this->writePartContentTo($content);
        $content->rewind();
        $streams = [ $this->streamFactory->newHeaderStream($this->part), $content ];

        /**
         * @var ParentHeaderPart
         */
        $part = $this->part;
        if ($part instanceof ParentHeaderPart && $part->getChildCount()) {
            $streams = array_merge($streams, $this->getBoundaryAndChildStreams($part));
        }

        return $streams;
    }