Key for the key-value data in Replicator. The type of the data value is defined in the key. KeySet are compared equal if the `id` strings are equal, i.e. use unique identifiers. Specific classes are provided for the built in data types, e.g. ORSetKeyT, and you can create your own keys.

public abstract class Key<T> : IKey<T>, 
	IKey
where T : IReplicatedData

[<AbstractClassAttribute>]
type Key<'T when 'T : IReplicatedData> =  
    class
        interface IKey<'T>
        interface IKey
    end