fsutil

type Options struct {
	// Pattern names the temp file as os.CreateTemp does: the last "*" is
	// replaced by a random string, and a pattern without one gets it appended.
	Pattern string
	// Guard, when set, runs before the temp file is created and returns the
	// func that releases it. The guard, AfterCreate and Track all run inside
	// it, so a caller's lock makes "temp exists" and "temp registered" one
	// step to any other holder. Guard is released exactly once, before any
	// byte is written.
	Guard func() (release func())
	// AfterCreate, when set, runs once the temp file exists, under the guard,
	// before Track. It is the window a test hooks.
	AfterCreate func(tmp string)
	// Track, when set, runs under the guard once the temp file exists and before
	// any byte is written, so a caller can record it for a signal handler. It
	// returns the func to call once the temp file is gone, renamed or removed.
	// An error refuses the write, and the temp file is removed.
	Track func(tmp string) (done func(), err error)
	// BeforeRename, when set, runs after the temp file is closed and before it
	// is renamed over the target. It is the window a test can hook.
	BeforeRename func()
}