How to add to index unpublished content by apachesolr? I use apachesolr module for index content. 
As I understand, this module does not provide indexing unpublished content. 
Is it some trick to avoid that?

I try to use this hook and change status callback, but it does not work.

function hook_apachesolr_entity_info_alter(&amp;$entity_info) {
  // Validate each entity if it can be indexed or not. Multiple callbacks are
  // allowed. If one of them returns false it won't be indexed
  $entity_info['node']['status callback'][] = 'apachesolr_index_node_status_callback';
}


p.s. it duplicate with this issue, but there no activity and it's very old.
You may want to follow this thread: Index unpublished nodes. There is no available patch right now but you'll find some hints to build your own custom module if you need to.