Copy microseconds in DateTime

lib/src/utils.dart

@@ -13,6 +13,7 @@ extension DateTimeRrule on DateTime {
     int? minute,
     int? second,
     int? millisecond,
+    int? microsecond,
     bool? isUtc,
   }) {
     return InternalDateTimeRrule.create(
@@ -23,7 +24,7 @@ extension DateTimeRrule on DateTime {
       minute: minute ?? this.minute,
       second: second ?? this.second,
       millisecond: millisecond ?? this.millisecond,
-      // Microseconds are not supported on web: https://github.com/dart-lang/sdk/issues/44876
+      microsecond: microsecond ?? this.microsecond,
       isUtc: isUtc ?? this.isUtc,
     );
   }
@@ -38,10 +39,20 @@ extension InternalDateTimeRrule on DateTime {
     int minute = 0,
     int second = 0,
     int millisecond = 0,
+    int microsecond = 0,
     bool isUtc = true,
   }) {
     final constructor = isUtc ? DateTime.utc : DateTime.new;
-    return constructor(year, month, day, hour, minute, second, millisecond);
+    return constructor(
+      year,
+      month,
+      day,
+      hour,
+      minute,
+      second,
+      millisecond,
+      microsecond,
+    );
   }
 
   static DateTime date(int year, [int month = 1, int day = 1]) {

test/recurrence_rule_test.dart

@@ -189,10 +189,19 @@ void main() {
         00,
         00,
         123, // milliseconds
+        456, // microseconds
       );
       final instances = rrule.getInstances(start: start);
 
       expect(instances.first, equals(start));
     },
   );
+  test('#48: DateTime.copyWith should preserve microseconds', () {
+    final start = DateTime(2023, 03, 20, 00, 00, 00, 0, 123);
+
+    expect(
+      start.copyWith(isUtc: true).copyWith(isUtc: false),
+      equals(start),
+    );
+  });
 }