Void GDALdllImageLineAllTouched (int nRasterXSize, int nRasterYSize,
Int nPartCount, int * panPartSize,
Double * padfX, double * padfY,
Double * padfVariant,
LlPointFunc pfnPointFunc, void * pCBData,
Int bAvoidBurningSamePoints);
The function of the last parameter is the meaning of what?