fix: avoid reconnecting to dependencies after cleanup (#14)

* fix: cancel reconnection when unsubscribing

* test: remove print

* feat: allow factory to return nil

* perf: use `next` iteration

src/sync/client.luau

@@ -36,7 +36,7 @@ local function client(options: ClientOptions): ClientSyncer
 		for index = 1, select("#", ...) do
 			local payload = select(index, ...)
 
-			for key, state in payload.data do
+			for key, state in next, payload.data do
 				if payload.type == "patch" then
 					atoms[key](patch.apply(atoms[key](), state))
 				else