isSameDay function
Check if it's same day
Implementation
bool isSameDay(int? previousMessageTime, int currentMessageTime) {
int? previousDay = previousMessageTime != null
? DateTime.fromMillisecondsSinceEpoch(previousMessageTime).day
: null;
int currentDay = DateTime.fromMillisecondsSinceEpoch(currentMessageTime).day;
int deltaDay = previousDay != null ? currentDay - previousDay : 1;
return deltaDay == 0;
}