fn diagnostics_subscriptions(
state: &RoomState,
user_id: &UserId,
connection_id: ConnectionId,
now: Instant,
) -> Vec<DiagnosticsSubscription>fn diagnostics_subscriptions(
state: &RoomState,
user_id: &UserId,
connection_id: ConnectionId,
now: Instant,
) -> Vec<DiagnosticsSubscription>