OptionalavatarOptionaldisplayIf true, the hero is from an MSC4186 summary, in which case displayName and avatarUrl will
have been set by the server if available. If false, the Hero has been constructed from a /v3/sync response,
so these fields will always be undefined.
A stripped m.room.member event which contains the key renderable fields from the event, sent only in simplified sliding sync (not
/v3/sync). This is very similar to MSC4186Hero from sliding-sync.ts but an internal format with camelCase rather than underscores.