Thread Safe Fibonacci Iterator

class Fibonacci implements Iterator<BigInteger> {
    private final AtomicReference<BigInteger> prev = new AtomicReference<>(ZERO);
    private final AtomicReference<BigInteger> curr = new AtomicReference<>(ONE);

    public boolean hasNext() {
        return true;
    }

    public BigInteger next() {
        while (true) {
            var prev = this.prev.get();
            var curr = this.curr.get();
            var nextCurr = ZERO == prev ? new BigInteger("1") : curr.add(prev);
            if (prev != curr && this.prev.get() == prev) {
                if (this.prev.compareAndSet(prev, curr)) {
                    this.curr.compareAndSet(curr, nextCurr);
                    return nextCurr;
                } else {
                    this.curr.compareAndSet(curr, nextCurr);
                }
            }
        }
    }
}