Function xgboost_sys::XGBoosterUpdateOneIter

pub unsafe extern "C" fn XGBoosterUpdateOneIter(
    handle: BoosterHandle,
    iter: c_int,
    dtrain: DMatrixHandle
) -> c_int

\brief update the model in one round using dtrain \param handle handle \param iter current iteration rounds \param dtrain training data \return 0 when success, -1 when failure happens