Aerys\Http1Driver::responseInitFilter PHP Method

    public static function responseInitFilter(InternalRequest $ireq)
    {
        $headers = yield;
        $status = $headers[":status"];
        $options = $ireq->client->options;
        if ($options->sendServerToken) {
            $headers["server"] = [SERVER_TOKEN];
        }
        if (!empty($headers[":aerys-push"])) {
            foreach ($headers[":aerys-push"] as $url => $pushHeaders) {
                $headers["link"][] = "<{$url}>; rel=preload";
            }
            unset($headers[":aerys-push"]);
        }
        $contentLength = $headers[":aerys-entity-length"];
        unset($headers[":aerys-entity-length"]);
        if ($contentLength === "@") {
            $hasContent = false;
            $shouldClose = $ireq->protocol === "1.0";
            if ($status >= 200 && $status != 204 && $status != 304) {
                $headers["content-length"] = ["0"];
            }
        } elseif ($contentLength !== "*") {
            $hasContent = true;
            $shouldClose = $ireq->protocol === "1.0";
            $headers["content-length"] = [$contentLength];
            unset($headers["transfer-encoding"]);
        } elseif ($ireq->protocol === "1.1") {
            $hasContent = true;
            $shouldClose = false;
            $headers["transfer-encoding"] = ["chunked"];
            unset($headers["content-length"]);
        } else {
            $hasContent = true;
            $shouldClose = true;
        }
        if ($hasContent) {
            $type = $headers["content-type"][0] ?? $options->defaultContentType;
            if (\stripos($type, "text/") === 0 && \stripos($type, "charset=") === false) {
                $type .= "; charset={$options->defaultTextCharset}";
            }
            $headers["content-type"] = [$type];
        }
        $remainingKeepAlives = $ireq->client->remainingKeepAlives;
        if ($shouldClose || $remainingKeepAlives <= 0) {
            $headers["connection"] = ["close"];
        } elseif ($remainingKeepAlives < PHP_INT_MAX) {
            $keepAlive = "timeout={$options->keepAliveTimeout}, max={$remainingKeepAlives}";
            $headers["keep-alive"] = [$keepAlive];
        } else {
            $keepAlive = "timeout={$options->keepAliveTimeout}";
            $headers["keep-alive"] = [$keepAlive];
        }
        $headers["date"] = [$ireq->httpDate];
        return $headers;
    }