r-lib/mirai: mirai 2.7.0

New Features

• Dispatcher reimplemented as a thread for lower overhead, removing the separate dispatcher process (#581).
• Adds memory argument to daemons() setting a memory budget (MB, metric) for queued task payloads at dispatcher, providing memory-based backpressure. This is opt-in and NULL (default) is unbounded (thanks @t-kalinowski, #454). Current and peak queued bytes (in MB) are surfaced under the memory field of status().
• Adds try_mirai(), a non-blocking variant of mirai() that returns NULL immediately if the dispatcher's memory budget is exhausted, instead of blocking. Useful in event-loop contexts (Shiny, promises) where blocking the host R thread is unacceptable.

Updates

• http_config() accepts ... forwarded to data when it is a function. This allows specifying custom resources as additional arguments, which are documented for Posit Workbench (thanks @michaelmayer2, #592).
• Fixes ssh_config() dropping the username from SSH URLs e.g. ssh://user@host (#583).
• Fixes transfer of large data (> ~2GB) on MacOS and Windows (#579).
• Fixes mirai_map() progress bar customization issues (thanks @mcol, #519).
• Fixes launch_remote() with http_config() failing for TLS connections, where newlines in the PEM certificate produced invalid JSON in the request payload.
• Improved performance and reduced memory consumption through optimizations in the underlying nanonext/NNG transport layer.
• Requires nanonext >= [1.8.2.9000].