setString method
Implementation
void setString(String key, String value) {
final ckey = key.toNativeUtf8().cast<ffi.Char>();
final cvalue = value.toNativeUtf8().cast<ffi.Char>();
cfeatures2d.cv_flann_IndexParams_setString(ref, ckey, cvalue);
calloc.free(ckey);
calloc.free(cvalue);
}