vfsi-fsspec

vfsi-fsspec is the backend-neutral buffering, batching, caching, callback, and transaction engine shared by the nfs4fs and vsmbfs distributions. Most users should install one of those protocol packages rather than this package directly.

Upgrade the protocol package (nfs4fs or vsmbfs) together with vfsi-fsspec. The shared engine requires native read_all_many support for per-call byte budgets and rejects older extensions before connecting; it never falls back to an unbounded read.

Partial open-ended cat_file reads and all open-ended cat_ranges reads use the EOF observed during size validation as their exclusive end. Later growth is excluded from that read, so it cannot exceed the checked allocation budget; truncation may produce a short read. This bounds the range, not a snapshot of its contents. Whole-file cat_file reads (normalized start zero, no end) retain the native read-to-EOF fast path, which enforces the allocation budget while reading.

Transactional writes require both a native creation-permissions API and a backend with POSIX permission support. Unsupported backends, including current SMB, reject transactional writes before allocating a spool or creating staging files; ordinary I/O remains supported. A method signature alone is not a capability.