SimpleTimeSerializer
Default KSerializer for SimpleTime - encodes as the string "HH:mm:ss.NNNNNNNNN", always in Asia/Kathmandu (the timezone all SimpleTimes in this library are anchored to). The nanosecond fractional part is omitted when nanosecond == 0 to keep wire payloads small.
Wire format examples:
"09:30:00""23:59:59.123456789"