How to attach an attachment to an email in D7 Bitrix?

Question

1C-Bitrix

There was an opportunity in CEvent, here they say that everything is the same, but I could not find it in the manuals and by experience

use Bitrix\Main\Mail\Event;
Event::send(array(
  "EVENT_NAME" => "FORM_OFFER",
  "LID" => "s1", 
  "C_FIELDS" => array(
    "POLE" => "ZNACHENIE"
  )
))

https://dev.1c-bitrix.ru/api_d7/bitrix/main/mail/e...

Answer 1

https://yadi.sk/i/a59pfaGq3MtEJi
judging by this, it is necessary to transfer the id of the file in the system to the FILE key, or the id array.