libraries/class-wp-session.php
protected function set_cookie() {
		@setcookie( WP_SESSION_COOKIE, $this->session_id . '||' . $this->expires . '||' . $this->exp_variant, $this->expires, COOKIEPATH, COOKIE_DOMAIN );
	}
protected function set_cookie() {
		@setcookie( WP_SESSION_COOKIE, $this->session_id . '||' . $this->expires . '||' . $this->exp_variant, $this->expires, COOKIEPATH, COOKIE_DOMAIN );
	}
Set the session cookie