blockTimestampToDate function
Convert block_timestamp_type
(half-seconds since a different epoch) to to date in ISO format */
Implementation
String blockTimestampToDate(int slot) {
var s = (DateTime.fromMillisecondsSinceEpoch(slot * 500 + 946684800000)).toIso8601String();
return s.substring(0, s.length - 1);
}