Bitrix. $_SESSION contents not visible in init.php?

Question

1C-Bitrix

Good afternoon.
I set in the file $_SESSION['test'] = $_POST['test'];
In init.php

require_once($_SERVER['DOCUMENT_ROOT'] . "/bitrix/modules/main/include/prolog_before.php");
print_r( $_SESSION );

Array
(
    [SALE_USER_ID] => 1
)

Why?

Answer 1

The session opens later. Page and order of its execution