docs: public final Index getIndex( String indexName,
                                   String workspaceName ) {
          logger().trace("Looking for index '{0}' in '{1}' provider for query in workspace '{2}'", indexName, getName(),
                         workspaceName);
          Map<String, AtomicIndex> byWorkspaceNames = providedIndexesByWorkspaceNameByIndexName.get(indexName);
          return byWorkspaceNames == null ? null : byWorkspaceNames.get(workspaceName);
      }