docs: public double addAndGet(double amount) {
      long v;
      double d;
      double n;
      long next;
      do {
        v = value.get();
        d = Double.longBitsToDouble(v);
        n = d + amount;
        next = Double.doubleToLongBits(n);
      } while (!value.compareAndSet(v, next));
      return n;
    }