Function lightgbm_sys::LGBM_BoosterGetNumFeature

pub unsafe extern "C" fn LGBM_BoosterGetNumFeature(
    handle: BoosterHandle, 
    out_len: *mut c_int
) -> c_int

\brief Get number of features. \param handle Handle of booster \param[out] out_len Total number of features \return 0 when succeed, -1 when failure happens