$pendingResponse = $http2stream->pendingResponse;

return yield $pendingResponse->promise();

        if ($windowSize > 0) {
            // Read next body chunk if less than 8192 bytes will remain in the buffer
            if ($length - 8192 < $windowSize && $stream->windowSizeIncrease) {
                $deferred = $stream->windowSizeIncrease;
                $stream->windowSizeIncrease = null;
                $deferred->resolve();
            }

            $data = $stream->requestBodyBuffer;
            $end = $windowSize - $this->frameSizeLimit;

            $stream->clientWindow -= $windowSize;
            $this->clientWindow -= $windowSize;

            for ($off = 0; $off < $end; $off  = $this->frameSizeLimit) {
                $this->writeFrame(
                    Http2Parser::DATA,
                    Http2Parser::NO_FLAG,
                    $stream->id,
                    \substr($data, $off, $this->frameSizeLimit)
                );
            }

            //stuck at writeFrame here:
            $promise = $this->writeFrame(
                Http2Parser::DATA,
                Http2Parser::NO_FLAG,
                $stream->id,
                \substr($data, $off, $windowSize - $off)
            );

            $stream->requestBodyBuffer = \substr($data, $windowSize);
            $stream->enableInactivityWatcher();

            return $promise;
        }