#' Save xgboost model to R's raw vector,
#' user can call xgb.load.raw to load the model back from raw vector
#'
#' Save xgboost model from xgboost or xgb.train
#'
#' @param model the model object.
#'
#' @examples
#' data(agaricus.train, package='xgboost')
#' data(agaricus.test, package='xgboost')
#' train <- agaricus.train
#' test <- agaricus.test
#' bst <- xgboost(data = train$data, label = train$label, max_depth = 2,
#'                eta = 1, nthread = 2, nrounds = 2,objective = "binary:logistic")
#' raw <- xgb.save.raw(bst)
#' bst <- xgb.load.raw(raw)
#' pred <- predict(bst, test$data)
#'
#' @export
xgb.save.raw <- function(model) {
  handle <- xgb.get.handle(model)
  .Call(XGBoosterModelToRaw_R, handle)
}