Output from stdout and stderr disappears when running `later` callback

System details:

Positron and OS details:

Positron Version: 2025.05.0 (Universal) build 35
Code - OSS Version: 1.98.0
Commit: ee0feaba9d71a3e9feef765e8c3a46aeb3273741
Date: 2025-04-09T03:27:32.927Z
Electron: 34.2.0
Chromium: 132.0.6834.196
Node.js: 20.18.2
V8: 13.2.152.36-electron.0
OS: Darwin arm64 24.3.0

Interpreter details:

R 4.4.2

Describe the issue:

This issue is related to #7235.

The later package is used for scheduling callbacks to be run, similar to setTimeout() in JavaScript. In Positron, when later runs a callback with the console idle, the output disappears.

If I run this in the terminal or in RStudio, it prints the message to the console:

later::later(\() {cat("Finished!")}, 0)

For example:

> later::later(\() {cat("Finished!")}, 0)
Finished!
>

But if I run it in Positron, nothing shows:

> later::later(\() {cat("Finished!")}, 0)
>

Same if I use stderr:

> later::later(\() {cat("Finished!", file=stderr())}, 0)
>

It does show up if I use later::run_now() to run the event loop immediately:

> later::later(\() {cat("Finished!")}, 0); later::run_now()
Finished!
>