Cant set multiple cookies in one request

When you set multiple cookies it only sets the first one. I have an application that has a csrf middleware, it one of the first middleware to be initialized. My app has a route where a we set a token then redirect to another page in the app, whats happening is the csrf middleware runs before the route function handler. The middleware sets a cookie, then the route function runs sets another cookie, then a redirect happens.

```
res.cookie("token", token, defaultCookieOpts));
```

SERVERLESS_EXPRESS:FORWARD_REQUEST_TO_NODE_SERVER:RESPONSE
```
_header: 'HTTP/1.1 302 Found\r\n' +
'X-DNS-Prefetch-Control: off\r\n' +
'X-Frame-Options: SAMEORIGIN\r\n' +
'Strict-Transport-Security: max-age=15552000; includeSubDomains\r\n' +
'X-Download-Options: noopen\r\n' +
'X-Content-Type-Options: nosniff\r\n' +
'X-XSS-Protection: 1; mode=block\r\n' +
'Referrer-Policy: same-origin\r\n' +
'Surrogate-Control: no-store\r\n' +
'Cache-Control: no-store, no-cache, must-revalidate, proxy-revalidate\r\n' +
'Pragma: no-cache\r\n' +
'Expires: 0\r\n' +
'Set-Cookie: _csrf=3A2IecjCunSB9Sq2rI-i-Ani; Path=/; SameSite=Strict\r\n' +
'Set-Cookie: token= on3N6MSlyG; Path=/; Expires=Fri, 31 Dec 9999 00:00:00 GMT\r\n' +
'Location: tx/austin/math-tutors/pro-1-fFWS9tC-z?leadKey=6lfLJiBTmXR&service=UCT7ybWAds\r\n' +
'Vary: Accept\r\n' +
'Content-Type: text/html; charset=utf-8\r\n' +
'Content-Length: 204\r\n' +
'Date: Tue, 20 Dec 2022 07:48:30 GMT\r\n' +
'Connection: keep-alive\r\n' +
'\r\n',
_keepAliveTimeout: 0,
_onPendingData: [Function: noopPendingOutput],
_sent100: false,
_expect_continue: false,
req: IncomingMessage {
_readableState: [ReadableState],
_events: [Object: null prototype] {},
_eventsCount: 0,
_maxListeners: undefined,
socket: [Object],
httpVersionMajor: '1',
httpVersionMinor: '1',
httpVersion: '1.1',
complete: true,
headers: [Object],
rawHeaders: [],
trailers: {},
rawTrailers: [],
aborted: false,
```

```
DEBUG {
message: 'SERVERLESS_EXPRESS:FORWARD_RESPONSE:EVENT_SOURCE_RESPONSE_PARAMS',
statusCode: 302,
body: '[BASE64_ENCODED]',
headers: [Object: null prototype] {
'x-dns-prefetch-control': 'off',
'x-frame-options': 'SAMEORIGIN',
'strict-transport-security': 'max-age=15552000; includeSubDomains',
'x-download-options': 'noopen',
'x-content-type-options': 'nosniff',
'x-xss-protection': '1; mode=block',
'referrer-policy': 'same-origin',
'surrogate-control': 'no-store',
'cache-control': 'no-store, no-cache, must-revalidate, proxy-revalidate',
pragma: 'no-cache',
expires: '0',
'set-cookie': [
'_csrf=3A2IecjCunSB9Sq2rI-i-Ani; Path=/; SameSite=Strict',

'token=on3N6MSlyG; Path=/; Expires=Fri, 31 Dec 9999 00:00:00 GMT'
],
location: '/pros/leads',
vary: 'Accept',
'content-type': 'text/html; charset=utf-8',
'content-length': '66'
},
isBase64Encoded: true
}
```
```
DEBUG {
message: 'SERVERLESS_EXPRESS:FORWARD_RESPONSE:EVENT_SOURCE_RESPONSE',
successResponse: '{\n' +
' statusCode: 302,\n' +
" body: 'PHA+Rm91bmQuIFJlZGlyZWN0aW5nIHRvIDxhIGhyZWY9InR4L2F1c3Rpbi9tYXRoLXR1dG9ycy9wcm8tMS1mRldTOXRDLXo/bGVhZEtleT02bGZMSmlCVG1YUiZhbXA7c2VydmljZT1VQ1Q3eWJXQWRzIj50eC9hdXN0aW4vbWF0aC10dXRvcnMvcHJvLTEtZkZXUzl0Qy16P2xlYWRLZXk9NmxmTEppQlRtWFImYW1wO3NlcnZpY2U9VUNUN3liV0FkczwvYT48L3A+',\n" +
' headers: {\n' +
" 'x-dns-prefetch-control': 'off',\n" +
" 'x-frame-options': 'SAMEORIGIN',\n" +
" 'strict-transport-security': 'max-age=15552000; includeSubDomains',\n" +
" 'x-download-options': 'noopen',\n" +
" 'x-content-type-options': 'nosniff',\n" +
" 'x-xss-protection': '1; mode=block',\n" +
" 'referrer-policy': 'same-origin',\n" +
" 'surrogate-control': 'no-store',\n" +
" 'cache-control': 'no-store, no-cache, must-revalidate, proxy-revalidate',\n" +
" pragma: 'no-cache',\n" +
" expires: '0',\n" +
" 'set-cookie': '_csrf=3A2IecjCunSB9Sq2rI-i-Ani; Path=/; SameSite=Strict',\n" +
" location: 'tx/austin/math-tutors/pro-1-fFWS9tC-z?leadKey=6lfLJiBTmXR&service=UCT7ybWAds',\n" +
" vary: 'Accept',\n" +
" 'content-type': 'text/html; charset=utf-8',\n" +
" 'content-length': '204'\n" +
' },\n' +
' multiValueHeaders: undefined,\n' +
' isBase64Encoded: true\n' +
'}',
body: '[BASE64_ENCODED]'
}
```

ソースファイルもテストも指定されていません。まず、serverless-express が Express のレスポンスヘッダーを AWS のレスポンスに変換する仕組みを追跡し、ログに表示されている set-cookie 配列と multiValueHeaders に注目してください。CSRF Cookie と token Cookie の両方を設定するリダイレクトを再現し、その後、転送されたレスポンスに両方の Cookie が保持されていることを確認してください。

索引モデルが issue の本文から書いたものです。