Enforced no-null check in NetworkCall

[WeAthFoLD]

It's almost unavoidable that we will encounter lookup failure in NetworkCalls. But doing null checks every time is really of great annoyance. I wonder whether we should add a noNull() flag in @Data and @Instance options, so NetworkCall can choose not to call the method at all when the argument is serialized to null.

[acaly]

Not sure which class you're talking about. But if a class should never be null, I suggest the exception be thrown in the serializer.
Well especially for entities (which can not be not-null), I agree there should be some improvements. We can add a parameter in Instance annotation to allow null check. And I think it's ok to enable the check on default. I think it's not necessary for Data or Updata.

[WeAthFoLD]

I think you are right. This happens mostly on lookup of TileEntities and Entities when synchronizing, in which case they should be guaranteed to be not null. Let's do it this way.