public static long calcCircularRefElementOffset(long index, long mask)
    {
        return REF_ARRAY_BASE + ((index & mask) << REF_ELEMENT_SHIFT);
    }
Note: circular arrays are assumed a power of 2 in length and the `mask` is (length - 1).

@param index desirable element index
@param mask (length - 1)
@return the offset in bytes within the circular array for a given index
jctools-core/src/main/java/org/jctools/util/UnsafeRefArrayAccess.java