Create thread in Microsoft Teams with Subject - microsoft-graph-api

Question

I'm currently trying to create a Microsoft teams thread (within a channel) via the Microsoft Graph API.
I'd like thread to have a subject/title and I'm sending the following request (from the graph explorer)
POST https://graph.microsoft.com/beta/teams/{teamId}/channels/{channelId}/chatThreads
with the following payload
{
"rootMessage": {
"body": {
"contentType": 1,
"content": "<h1>Hello world</h1>"
},
"subject": "Welcome Aboard!"
}
}
However the thread that gets created doesn't have any title as you can see on the following screen capture.
So the question is: how can I create a chat thread with a subject from the Microsoft Graph API?
Edit: here is the payload I get for the message "title from teams" (which was created from the UI), note is contains a subject attribute.
{
"replyToId": null,
"etag": "1537198542791",
"messageType": "message",
"createdDateTime": "2018-09-17T15:35:42.791Z",
"lastModifiedDateTime": null,
"deleted": false,
"subject": "title from teams",
"summary": null,
"importance": "normal",
"locale": "en-us",
"id": "1537198542791",
"from": {
"application": null,
"device": null,
"user": {
"id": "c2e8df37-c6a7-4d88-89b1-feb4f1fda7c5",
"displayName": "Vincent Biret",
"identityProvider": "Aad"
}
},
"body": {
"contentType": "text",
"content": "wvwvwevw"
},
"attachments": [],
"mentions": [],
"reactions": []
}

Answer 1

There is no "subject" for a post in Microsoft Teams. These are chat threads, not email threads. The only content is the body:
{
"rootMessage": {
"body": {
"contentType": 1,
"content": "<h1>Hello world</h1>"
}
}
}