Can exclude components which are unknown at the time of creating the query that have been declared to write to the same component. This allows for extending systems of components safely without editing the previously existing systems. The goal is to have a way for systems that expect to transform data from one set of components (inputs) to another (output[s]) be able to declare that explicit transform, and they exclusively know about one set of inputs. If there are other inputs that want to write to the same output, the query shouldn't match because it's a nonsensical/unhandled setup. It's both a way to guard against nonsensical components (having two systems write to the same output value), and a way to "turn off" existing systems/queries by putting a component with the same write lock on an entity, letting another system handle it.

[AttributeUsage(AttributeTargets.Struct, AllowMultiple = true)]public class WriteGroupAttribute : Attribute