Create a read-only copy of a reactiveValues() object

[nbenn]

While reactiveValues() objects have a readonly flag, I could not find a way to manipulate this attribute. In my use case (which I'm happy to elaborate on), I'd like to create a ready-only copy of a reactiveValues() object and the only option I could find was "circumventing" the API by doing something like

make_read_only <- function(x) {

   res <- unclass(x)
   res[["readonly"]] <- TRUE
   class(res) <- class(x)

   res
 }

Exposing such functionality as part of the "public" API might be useful.