Issue #3257363 by samuel.mortenson: Always import users first, if you can

      }

      $chunked_graph[] = $chunk;

    }

    // Always import users first if possible.

    if (!empty($chunked_graph)) {

      $user_chunk = [];

      foreach ($chunked_graph[0] as $i => $id) {

        if (strpos($id, 'user.') === 0) {

          $user_chunk[] = $id;

          unset($chunked_graph[0][$i]);

        }

      }

      if (empty($chunked_graph[0])) {

        $chunked_graph[0] = $user_chunk;

      }

      elseif (!empty($user_chunk)) {

        $chunked_graph[0] = array_values($chunked_graph[0]);

        array_unshift($chunked_graph, $user_chunk);

      }

    }

    return $chunked_graph;

  }