Converts this TimeOfDay to a string with the format HH:MM:SS. If writer is set, the resulting string will be written directly to it.
A char accepting output range
A string when not using an output range; void otherwise.
assert(TimeOfDay(0, 0, 0).toISOExtString() == "00:00:00"); assert(TimeOfDay(12, 30, 33).toISOExtString() == "12:30:33");
See Implementation
Converts this TimeOfDay to a string with the format HH:MM:SS. If writer is set, the resulting string will be written directly to it.