/api/playback/state/{itemId}/mark-watched

{
  "session": {
    "id": "string",
    "userId": "string",
    "profileId": "string",
    "itemId": "string",
    "fileId": "string",
    "libraryId": "string",
    "mediaType": "string",
    "source": "tracked",
    "status": "active",
    "startPosition": 0,
    "endPosition": 0,
    "duration": 0,
    "secondsWatched": 0,
    "pagesRead": 0,
    "completed": true,
    "playbackFormat": "direct_play",
    "videoCodec": "string",
    "audioCodec": "string",
    "container": "string",
    "clientName": "string",
    "userAgent": "string",
    "clientIp": "string",
    "startedAt": "string",
    "endedAt": "string",
    "lastHeartbeatAt": "string"
  }
}

{
  "error": "string"
}