```ruby
require 'watch'

class LibWatch < Watch
  def on_change(directory)
    puts "Ruby callback: #{directory.inspect}"
  end
end

l = LibWatch.new

p l.latency
l.latency = 0.2
p l.latency

# l.watch_directories "."
l.watch_directories %w(. /tmp)

l.run
```

Update example to new library name
user
```ruby
require File.dirname(__FILE__) + '/../ext/fs_event'

class PrintChange < FsEvent
  def on_change(directories)
    puts "Detected change in: #{directories.inspect}"
  end

  def run
    puts "watching #{registered_directories.join(", ")} for changes"
    super
  end
end

printer = PrintChange.new
printer.latency = 0.2
printer.watch_directories %w(. /tmp)
printer.run
```
assistant