карта мурлыка работает, но будущая карта мурра не работает

Question

В следующем коде map_dfr из purrr работает, но future_map_dfr из furrr выдает ошибку.Как я могу это исправить?

    #install.packages("randomForest"); install.packages("tidyverse"); install.packages("iml")
    library(tidyverse); library(iml); library(randomForest) 
    library(furrr)

    plan(multiprocess)

    set.seed(42)

    mtcars1 <- mtcars %>%  mutate(vs = as.factor(vs),
                                  id = row_number())

x <- "vs"
y <- paste0(setdiff(setdiff(names(mtcars1), "vs"), "id"), collapse = "+")

rf = randomForest(as.formula(paste0(x, "~ ", y)), data = mtcars1, ntree = 50)

predictor <- Predictor$new(rf, data = mtcars1, y = mtcars1$vs)

# Results using map_dfr() from purrr
shapelyresults <- map_dfr(1:nrow(mtcars), ~(Shapley$new(predictor, x.interest = mtcars1[.x,]) %>% 
                                              .$results %>% 
                                              as_tibble() %>% 
                                              arrange(desc(phi)) %>% 
                                              slice(1:5) %>% 
                                              select(feature.value, phi) %>%
                                              mutate(id = .x)))

# Attempt to use future_map_dfr() from furrr
f_shapelyresults <- future_map_dfr(1:nrow(mtcars), ~(Shapley$new(predictor, x.interest = mtcars1[.x,]) %>% 
                                              .$results %>% 
                                              as_tibble() %>% 
                                              arrange(desc(phi)) %>% 
                                              slice(1:5) %>% 
                                              select(feature.value, phi) %>%
                                              mutate(id = .x)))