Expose get_fdset() (#784)

By extracting the fdset from the connection

Fixes #767

Author: hadley

R/req-perform-connection.R

@@ -219,6 +219,12 @@ StreamingBody <- R6::R6Class(
       !isIncomplete(private$conn)
     },
 
+    #' @description Get the active file descriptions and timeout from the
+    #'   handle. Wrapper around [curl::multi_fdset()].
+    get_fdset = function() {
+      curl::multi_fdset(private$conn)
+    },
+
     #' @description Close the connection
     close = function() {
       if (self$is_open()) {

man/StreamingBody.Rd

@@ -100,3 +100,13 @@ test_that("validates its input", {
     StreamingBody$new(1)
   })
 })
+
+test_that("can access fdset", {
+  skip_on_cran()
+
+  con <- curl::curl(example_url('/drip'), open = 'rb')
+  on.exit(close(con))
+
+  body <- StreamingBody$new(con)
+  expect_length(body$get_fdset()$reads, 1)
+})