[
  {
    "registrant_id": "R-1801",
    "webinar_id": "W-0918",
    "device": "pc",
    "joined_at": "2026-09-18T14:02:00+09:00",
    "left_at": "2026-09-18T14:54:00+09:00",
    "questions_asked": 2
  },
  {
    "registrant_id": "R-1803",
    "webinar_id": "W-0918",
    "device": "mobile",
    "joined_at": "2026-09-18T14:05:00+09:00",
    "left_at": "2026-09-18T14:11:00+09:00",
    "questions_asked": 0
  },
  {
    "registrant_id": "R-1803",
    "webinar_id": "W-0918",
    "device": "pc",
    "joined_at": "2026-09-18T14:06:00+09:00",
    "left_at": "2026-09-18T14:20:00+09:00",
    "questions_asked": 0
  },
  {
    "registrant_id": "R-1804",
    "webinar_id": "W-0918",
    "device": "pc",
    "joined_at": "2026-09-18T14:00:30+09:00",
    "left_at": "2026-09-18T14:58:00+09:00",
    "questions_asked": 1
  },
  {
    "registrant_id": "R-1805",
    "webinar_id": "W-0918",
    "device": "pc",
    "joined_at": "2026-09-18T14:03:00+09:00",
    "left_at": "2026-09-18T14:40:00+09:00",
    "questions_asked": 0
  },
  {
    "registrant_id": "R-1805",
    "webinar_id": "W-0918",
    "device": "mobile",
    "joined_at": "2026-09-18T14:30:00+09:00",
    "left_at": "2026-09-18T14:47:00+09:00",
    "questions_asked": 0
  },
  {
    "registrant_id": "R-1806",
    "webinar_id": "W-0918",
    "device": "pc",
    "joined_at": "2026-09-18T14:10:00+09:00",
    "left_at": "2026-09-18T14:16:00+09:00",
    "questions_asked": 0
  },
  {
    "registrant_id": "R-1806",
    "webinar_id": "W-0918",
    "device": "pc",
    "joined_at": "2026-09-18T14:20:00+09:00",
    "left_at": "2026-09-18T14:31:00+09:00",
    "questions_asked": 0
  },
  {
    "registrant_id": "R-1807",
    "webinar_id": "W-0918",
    "device": "mobile",
    "joined_at": "2026-09-18T14:15:00+09:00",
    "left_at": "2026-09-18T14:22:00+09:00",
    "questions_asked": 1
  },
  {
    "registrant_id": "R-1808",
    "webinar_id": "W-0918",
    "device": "pc",
    "joined_at": "2026-09-18T14:01:00+09:00",
    "left_at": null,
    "questions_asked": 0
  },
  {
    "registrant_id": "R-1810",
    "webinar_id": "W-0918",
    "device": "pc",
    "joined_at": "2026-09-18T14:00:00+09:00",
    "left_at": "2026-09-18T14:20:00+09:00",
    "questions_asked": 0
  },
  {
    "registrant_id": "R-2501",
    "webinar_id": "W-0925",
    "device": "pc",
    "joined_at": "2026-09-25T16:01:00+09:00",
    "left_at": "2026-09-25T16:29:00+09:00",
    "questions_asked": 0
  },
  {
    "registrant_id": "R-2503",
    "webinar_id": "W-0925",
    "device": "pc",
    "joined_at": "2026-09-25T16:00:00+09:00",
    "left_at": "2026-09-25T16:52:00+09:00",
    "questions_asked": 3
  }
]