library(parallel)

if(require(boot, quietly = TRUE)) {
    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)
}