Transfer large objects through `socketConnection` in R fails on macOS

Question

I am trying to transfer a large object from a session to another using a socketConnection. With the following I can establish the connection between the two session and see that it works for small messages:

socket <- serverSocket(11927)

r <- callr::r_session$new()
r$call(function() {
  assign(
    "conection",
    socketConnection(port = 11927, open = "wb", blocking = TRUE, server = FALSE),
    envir = .GlobalEnv
  )
  NULL
})

con <- socketAccept(socket, open = "wb", blocking = TRUE)
close(socket)
r$read()

serialize("hello world", con)

r$run(function() {
  serialize(paste("hello from there: ", unserialize(conection)), conection)
})

unserialize(con)

Now if I try to serialize a large value, for example:

r$run(function() {
  x <- runif(256*256*3)
  serialize(x, conection)
  TRUE
})

The serialization never finishes. It's worth noting that this works as expected on Linux. I didn't try on Windows.

I think this should work correctly because, using the parallel package, that also uses socket connections to transfer objects everything works as expected and I can transfer large objects pretty quickly. For example:

cl <- parallel::makePSOCKcluster(1)

parallel::clusterEvalQ(cl,  {
  get_batch <- function() runif(256*256*3)
})

out <- parallel::clusterCall(cl, "get_batch")

Any idea on what could be causing this behavior on macOS?