copies-rust: move CPU-heavy Rust processing into a child thread...
copies-rust: move CPU-heavy Rust processing into a child thread
… that runs in parallel with the parent thread fetching data.
This can be disabled through a new config. CLI example:
hg --config=devel.copy-tracing.multi-thread=no
For now both threads use the GIL, later commits will reduce this.
Differential Revision:
https://phab.mercurial-scm.org/D9684