HTTP/2 causing 400 errors on nginx

[danog]

Usage of HTTP/2 for multiple concurrent POST requests causes 400 errors on nginx 1.18.0, switching to HTTP/1.1 fixes everything.

Reproduces even without concurrent requests with the following form body:

            $data = \file_get_contents('https://github.com/danog/rpc-db/releases/download/latest/core.json');
            $finfo = new finfo(FILEINFO_MIME_TYPE);

            $bodyNew = new Form();
            $bodyNew->addStream("0", BufferedContent::fromString($data, $finfo->buffer($data)), \basename($href));
            $newPage = new Request(Pusher::PUSH_FILE, 'POST');
            $newPage->setBody($bodyNew);

[danog]

May or may not be caused by an issue in the recent GOAWAY fixes