Update FrameData docs for correct usage

         *

         * @param data The payload which includes frame information. Divide nanosecond values by

         *             {@code 1000000} to convert it to the {@link SystemClock#uptimeMillis()}

         *             time base.

         *             time base. {@code data} is not valid outside of {@code onVsync} and should

         *             not be accessed outside the callback.

         * @see FrameCallback#doFrame

         **/

        void onVsync(@NonNull FrameData data);