[nequo]

There is also this in the futureverse if you like for loop style code more:

  library(doFuture)
  plan(multisession)

  y <- foreach(x = 1:4, y = 1:10) %dofuture% {
    z <- x + y
    slow_sqrt(z)
  }

https://dofuture.futureverse.org/