Fix registerCustomWatcher to allow nulls (#107)

The idea behind the closures passed to `registerCustomWatcher` is that
they should return `null` if the particular implementation does not
support the provided path (in which case we should fallback to other
implementations).

Modified a test to check this.
2 files changed
tree: a9abc9b61381f820c705b8b2912df7e787a16a5d
  1. .gitignore
  2. .test_config
  3. .travis.yml
  4. CHANGELOG.md
  5. LICENSE
  6. README.md
  7. analysis_options.yaml
  8. benchmark/
  9. example/
  10. lib/
  11. pubspec.yaml
  12. test/
README.md

A file system watcher.

It monitors changes to contents of directories and sends notifications when files have been added, removed, or modified.