lazy_write and empty sessions

test.phpt

--TEST--
session.lazy_write triggers updateTimestamp callback when session remains empty
--INI--
session.lazy_write=1
--FILE--
<?php
class MySessionHandler implements SessionHandlerInterface#, SessionUpdateTimestampHandlerInterface
{
    public function close() {
        return TRUE;
    }
 
    public function destroy($sessid) {
        return TRUE;
    }
 
    public function gc($maxlifetime) {
        return TRUE;
    }
 
    public function open($path, $sessname) {
        return TRUE;
    }
 
    public function read($sessid) {
        return '';
    }
 
    public function write($sessid, $sessdata) {
        echo __FUNCTION__, PHP_EOL;
        return TRUE;
    }

    public function updateTimestamp($sessid, $sessdata) {
        echo __FUNCTION__, PHP_EOL;
        return TRUE;
    }
}

$handler = new MySessionHandler();
session_set_save_handler($handler);
session_id(md5(''));
session_start();
--EXPECT--
updateTimestamp