The browser sometimes cannot launch due to profile's singleton lock

[yhatt]

Version of Marp Tool

Marp CLI v3.4.0

Operating System

macOS

Environment

• OS version: macOS Sonoma 14.6.1
• Node.js version (Marpit / Marp Core/ Marp CLI): v20.11.0
• VS Code version (Marp for VS Code): VS Code 1.93.0

How to reproduce

1. Launch Marp CLI with server mode: marp -s .
2. Show an any Markdown slide as PDF: http://localhost:8080/markdown.md?pdf
3. Try to convert some Markdown into PDF with another Marp CLI process (e.g. Export command in Marp for VS Code)

Expected behavior

Success exporting PDF in step 3

Actual behavior

Failure to export: [CLIError] Failed converting Markdown. (Failed to launch the browser process! undefined
[31630:259:0912/234955.283762:ERROR:process_singleton_posix.cc(335)] Failed to create /private/var/folders/q3/skswxg4x7934y_xc5vjbyhrw0000gn/T/marp-cli-conversion/SingletonLock: File exists (17)
[31630:259:0912/234955.283936:ERROR:chrome_main_delegate.cc(592)] Failed to create a ProcessSingleton for your profile directory. This means that running multiple instances would start multiple browser processes rather than opening a new window in the existing process. Aborting now to avoid profile corruption.


TROUBLESHOOTING: https://pptr.dev/troubleshooting
)

Additional information

The current Chrome seems to be strictly managed to start the profile in a single process. We are currently using named temporary directory as the Chrome's data dir, but we have to consider to name them as unique.