Function from_fs_watch 

pub fn from_fs_watch<P>(paths: impl IntoIterator<Item = P>) -> Operator<FsEvent>
where
    P: Into<PathBuf>,

from_fs_watch: filesystem watcher source.

Filesystem callbacks enqueue host events; the graph-local async driver drains that queue back through DeferredCtx, keeping graph state on the local source boundary. The visible factory name is fromFSWatch, matching the clean-slate TS source catalog without making this a parity surface.