poll

type Config struct {
	// Directory for downloaded files
	TempDir string

	// True to only show commands w/o executing them
	DryRun bool

	// URL:port of the sftp server to poll
	HostPort string

	// ssh configuration
	Ssh *ssh.ClientConfig
}

type Poller interface {
	io.Closer
	Updates() <-chan *Update
}

type Update struct {
	Path      string
	Timestamp time.Time
}