Drush command "solr-index" cannot be run

Looks like there's a couple function calls to undefined functions for the index command, which will give you a nice fatal PHP error :)

function apachesolr_drush_solr_index() {
  module_load_include('inc', 'apachesolr', 'apachesolr.admin');
  apachesolr_batch_index_remaining();
  drush_backend_batch_process();
}

Neither of those two appear anywhere in the module, much less in apachesolr.admin.inc