Issue with modeling in serde

example_easy.json

            {
              "origin_server_ts": 1512357670852,
              "sender": "@kit:example.com",
              "event_id": "$15123576704435ruveN:example.com",
              "unsigned": {
                "age": 12377
              },
              "content": {
                "body": "previous message redacted as a test",
                "msgtype": "m.text"
              },
              "type": "m.room.message"
            }

example_hard.json

            {
              "origin_server_ts": 1512357552733,
              "sender": "@kit:example.com",
              "event_id": "$15123575524433DhyJd:example.com",
              "unsigned": {
                "age": 130496,
                "redacted_by": "$15123575574434ZOAuz:example.com",
                "redacted_because": {
                  "origin_server_ts": 1512357557654,
                  "sender": "@kit:example.com",
                  "event_id": "$15123575574434ZOAuz:example.com",
                  "unsigned": {
                    "age": 125575
                  },
                  "content": {},
                  "redacts": "$15123575524433DhyJd:example.com",
                  "type": "m.room.redaction"
                }
              },
              "content": {},
              "type": "m.room.message"
            },