pub type GDALDerivedPixelFunc = Option<unsafe extern "C" fn(papoSources: *mut *mut c_void, nSources: c_int, pData: *mut c_void, nBufXSize: c_int, nBufYSize: c_int, eSrcType: Type, eBufType: Type, nPixelSpace: c_int, nLineSpace: c_int) -> Type>;