rhg: Add lazy/cached dirstate data file ID parsing on Repo The `dirstate_parents`, `dirstate_data_file_uuid`, and `dirstate_map` members of `Repo` can be access in any order and the `.hg/dirstate` file should only be opened once. Differential Revision: https://phab.mercurial-scm.org/D11838

rhg: Make Repo::dirstate_parents a LazyCell Unify with the same abstraction used for other lazily-initialized components Differential Revision: https://phab.mercurial-scm.org/D11837

rust: Add Vfs::write_atomic This method writes to a temporary file then renames in place Differential Revision: https://phab.mercurial-scm.org/D11836

rhg: Initial repository locking Initial Rust implementation of locking based on the `.hg/wlock` symlink (or file), with lock breaking when the recorded pid and hostname show that a lock was left by a local process that is not running anymore (as it might have been killed). Differential Revision: https://phab.mercurial-scm.org/D11835

rust: Serializing a DirstateMap does not mutate it anymore Differential Revision: https://phab.mercurial-scm.org/D11834

rhg: don't run `blackbox` if not activated You currently have no way of turning off blackbox. Aside from being a bug, this can be annoying if you use `rhg` in your shell prompt, but also because the current implementation of blackbox is quite slow due to `user` querying. Differential Revision: https://phab.mercurial-scm.org/D11813

rust: add function to check if an extension is enabled This will be used in the next patch Differential Revision: https://phab.mercurial-scm.org/D11812

dirstate: remove unused method Its last usage was inlined in `merge.py`. Differential Revision: https://phab.mercurial-scm.org/D11849

fsmonitor: fix criteria for nonnormalset computation ... oops. Differential Revision: https://phab.mercurial-scm.org/D11875

fsmonitor: incorporate fixes for Python 3.10 (issue6612) Differential Revision: https://phab.mercurial-scm.org/D11862