public static int arrayIndexScale(final Class<?> clazz) {
        return hasUnsafe() ? UNSAFE_ACCESSOR.arrayIndexScale(clazz) : -1;
    }
Reports the scale factor for addressing elements in the storage
allocation of a given array class.
jraft-core/src/main/java/com/alipay/sofa/jraft/util/internal/UnsafeUtil.java