SysTime.toISOExtString with timezone offset

[Jack Applegame via Digitalmars-d-learn]

I need current system time ISO string with timezone offset. For 
example
"2015-04-20T11:00:44.735441+03:00"
but Clock.currTime.toISOExtString doesn't write offset:
"2015-04-20T11:00:44.735441+03:00"
I found workaround, but it looks redundant and needs memory 
allocation:

auto t = Clock.currTime;
t.timezone = new immutable SimpleTimeZone(t.utcOffset);
writeln(t.toISOExtString);

Is there a simple way to get time ISO string with timezone offset?