vagrant@d7project:~$ drush --debug --root=/var/www/d7project/docroot/docroot
Drush Launcher Version: 0.6.0
ROOT: /var/www/d7project/docroot/docroot
DRUSH VERSION: 8
DRUPAL ROOT: /var/www/d7project/docroot/docroot/docroot
COMPOSER ROOT: /var/www/d7project/docroot/docroot
VENDOR ROOT: /var/www/d7project/docroot/docroot/vendor
Cache HIT cid: 8.1.18-commandfiles-0-a6735ad2ab018a8cdaf70df56ee6bff3 [0.02 sec, 2.76 MB]                                                                                  [debug]
Bootstrap to phase 0. [0.15 sec, 7.06 MB]                                                                                                                              [bootstrap]
Bootstrap to phase -1. [0.15 sec, 7.06 MB]                                                                                                                             [bootstrap]
Found command: help (commandfile=help) [0.15 sec, 7.06 MB]                                                                                                             [bootstrap]
Loading outputformat engine. [0.15 sec, 7.06 MB]                                                                                                                          [notice]
Calling hook drush_core_help [0.16 sec, 7.31 MB]                                                                                                                           [debug]
...