src/main/java/com/workplacesystems/utilsj/collections/IterativeCallback.java
public IterativeState<T,R> setState(IterativeState<T,R> new_state)
    {
        IterativeState<T,R> old_state = this.state;
        this.state = new_state;
        return old_state;
    }
public IterativeState<T,R> setState(IterativeState<T,R> new_state)
    {
        IterativeState<T,R> old_state = this.state;
        this.state = new_state;
        return old_state;
    }
Sets the supplied state for this IterativeCallback.

@return previous state