R version 3.6.2 Patched (2020-02-12 r77795) -- "Dark and Stormy Night"
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Platform: x86_64-pc-linux-gnu (64-bit)

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> library(parallel)
> 
> if(require(boot)) {
+     cd4.rg <- function(data, mle) MASS::mvrnorm(nrow(data), mle$m, mle$v)
+     cd4.mle <- list(m = colMeans(cd4), v = var(cd4))
+     mc <- getOption("mc.cores", 2)
+     run1 <- function(...) boot(cd4, corr, R = 500, sim = "parametric",
+                                ran.gen = cd4.rg, mle = cd4.mle)
+     ## To make this reproducible:
+     set.seed(123, "L'Ecuyer"); mc.reset.stream()
+     res <- mclapply(seq_len(mc), run1)
+     cd4.boot <- do.call(c, res)
+     boot.ci(cd4.boot,  type = c("norm", "basic", "perc"),
+             conf = 0.9, h = atanh, hinv = tanh)
+ }
Loading required package: boot
BOOTSTRAP CONFIDENCE INTERVAL CALCULATIONS
Based on 1000 bootstrap replicates

CALL : 
boot.ci(boot.out = cd4.boot, conf = 0.9, type = c("norm", "basic", 
    "perc"), h = atanh, hinv = tanh)

Intervals : 
Level      Normal              Basic              Percentile     
90%   ( 0.4575,  0.8547 )   ( 0.4703,  0.8575 )   ( 0.4964,  0.8663 )  
Calculations on Transformed Scale;  Intervals on Original Scale
> 
> proc.time()
   user  system elapsed 
  0.373   0.114   0.367