Merge "Fix overflow sanitizer in copyWithAuthor."

        // mEvent, mLength, mData[...], duplicate mLength

        static const size_t kOverhead = sizeof(entry) + sizeof(ending);

        // endind length of previous entry

        static const size_t kPreviousLengthOffset = - sizeof(ending) +

        static const ssize_t kPreviousLengthOffset = - sizeof(ending) +

            offsetof(ending, length);

    };