| void OffsetIndexBy | ( | ref int | index, | 
| int | offset | ||
| ) | 
Offsets, the provided index by the offset parameter, the wraps the result. The value passed in is adjusted directly via the ref parameter keyword. No value is returned.
| index | the index to adjust downwards by the offset amount | 
| offset | the amount to adjust the index by. may be positive or negative. |