We could error here if `path` and `sourceList` aren't on the session.  We should deal with those before we start to use them.  Move that global `options` object into a module that you require so you can pass it in here:

```javascript
var syncOptions = require('./lib/sync-options.js');
...
rsync.checksums(fs, ...., syncOptions, ...)
```

Or declare it inline if it isn't shared in other places.