Update date_time.dart

Changed _native to public field

lib/src/date_time.dart

@@ -14,7 +14,7 @@ class TZDateTime implements DateTime {
   static const int minMillisecondsSinceEpoch = -maxMillisecondsSinceEpoch;
 
   /// Returns the native [DateTime] object.
-  static DateTime _toNative(DateTime t) => t is TZDateTime ? t._native : t;
+  static DateTime _toNative(DateTime t) => t is TZDateTime ? t.native : t;
 
   /// Converts a [_localDateTime] into a correct [DateTime].
   static DateTime _utcFromLocalDateTime(DateTime local, Location location) {
@@ -66,7 +66,7 @@ class TZDateTime implements DateTime {
   /// Native [DateTime] used as canonical, utc representation.
   ///
   /// Represents the same moment as this [TZDateTime].
-  final DateTime _native;
+  final DateTime native;
 
   /// The number of milliseconds since
   /// the "Unix epoch" 1970-01-01T00:00:00Z (UTC).
@@ -77,7 +77,7 @@ class TZDateTime implements DateTime {
   /// 8,640,000,000,000,000ms (100,000,000 days) from the Unix epoch.
   /// In other words: [:millisecondsSinceEpoch.abs() <= 8640000000000000:].
   @override
-  int get millisecondsSinceEpoch => _native.millisecondsSinceEpoch;
+  int get millisecondsSinceEpoch => native.millisecondsSinceEpoch;
 
   /// The number of microseconds since the "Unix epoch"
   /// 1970-01-01T00:00:00Z (UTC).
@@ -91,7 +91,7 @@ class TZDateTime implements DateTime {
   /// Note that this value does not fit into 53 bits (the size of a IEEE
   /// double).  A JavaScript number is not able to hold this value.
   @override
-  int get microsecondsSinceEpoch => _native.microsecondsSinceEpoch;
+  int get microsecondsSinceEpoch => native.microsecondsSinceEpoch;
 
   /// [Location]
   final Location location;
@@ -224,10 +224,10 @@ class TZDateTime implements DateTime {
                 ? TimeZone.UTC
                 : location.timeZone(other.millisecondsSinceEpoch));
 
-  TZDateTime._(DateTime native, this.location, this.timeZone)
-      : _native = native,
+  TZDateTime._(DateTime nativeDate, this.location, this.timeZone)
+      : native = nativeDate,
         _localDateTime =
-            _isUtc(location) ? native : native.add(_timeZoneOffset(timeZone));
+            _isUtc(location) ? nativeDate : nativeDate.add(_timeZoneOffset(timeZone));
 
   /// Constructs a new [TZDateTime] instance based on [formattedString].
   ///
@@ -258,13 +258,13 @@ class TZDateTime implements DateTime {
   ///
   /// Returns [this] if it is already in UTC.
   @override
-  TZDateTime toUtc() => isUtc ? this : TZDateTime.from(_native, UTC);
+  TZDateTime toUtc() => isUtc ? this : TZDateTime.from(native, UTC);
 
   /// Returns this DateTime value in the local time zone.
   ///
   /// Returns [this] if it is already in the local time zone.
   @override
-  TZDateTime toLocal() => isLocal ? this : TZDateTime.from(_native, local);
+  TZDateTime toLocal() => isLocal ? this : TZDateTime.from(native, local);
 
   static String _fourDigits(int n) {
     var absN = n.abs();
@@ -345,17 +345,17 @@ class TZDateTime implements DateTime {
   /// Returns a new [TZDateTime] instance with [duration] added to [this].
   @override
   TZDateTime add(Duration duration) =>
-      TZDateTime.from(_native.add(duration), location);
+      TZDateTime.from(native.add(duration), location);
 
   /// Returns a new [TZDateTime] instance with [duration] subtracted from
   /// [this].
   @override
   TZDateTime subtract(Duration duration) =>
-      TZDateTime.from(_native.subtract(duration), location);
+      TZDateTime.from(native.subtract(duration), location);
 
   /// Returns a [Duration] with the difference between [this] and [other].
   @override
-  Duration difference(DateTime other) => _native.difference(_toNative(other));
+  Duration difference(DateTime other) => native.difference(_toNative(other));
 
   /// Returns true if [other] is a [TZDateTime] at the same moment and in the
   /// same [Location].
@@ -373,7 +373,7 @@ class TZDateTime implements DateTime {
   bool operator ==(Object other) {
     return identical(this, other) ||
         other is TZDateTime &&
-            _native.isAtSameMomentAs(other._native) &&
+            native.isAtSameMomentAs(other.native) &&
             location == other.location;
   }
 
@@ -389,7 +389,7 @@ class TZDateTime implements DateTime {
   /// assert(berlinWallFell.isBefore(moonLanding) == false);
   /// ```
   @override
-  bool isBefore(DateTime other) => _native.isBefore(_toNative(other));
+  bool isBefore(DateTime other) => native.isBefore(_toNative(other));
 
   /// Returns true if [this] occurs after [other].
   ///
@@ -403,7 +403,7 @@ class TZDateTime implements DateTime {
   /// assert(berlinWallFell.isAfter(moonLanding) == true);
   /// ```
   @override
-  bool isAfter(DateTime other) => _native.isAfter(_toNative(other));
+  bool isAfter(DateTime other) => native.isAfter(_toNative(other));
 
   /// Returns true if [this] occurs at the same moment as [other].
   ///
@@ -418,7 +418,7 @@ class TZDateTime implements DateTime {
   /// ```
   @override
   bool isAtSameMomentAs(DateTime other) =>
-      _native.isAtSameMomentAs(_toNative(other));
+      native.isAtSameMomentAs(_toNative(other));
 
   /// Compares this [TZDateTime] object to [other],
   /// returning zero if the values occur at the same moment.
@@ -427,10 +427,10 @@ class TZDateTime implements DateTime {
   /// if this [TZDateTime] is smaller (earlier) than [other],
   /// or a positive integer if it is greater (later).
   @override
-  int compareTo(DateTime other) => _native.compareTo(_toNative(other));
+  int compareTo(DateTime other) => native.compareTo(_toNative(other));
 
   @override
-  int get hashCode => _native.hashCode;
+  int get hashCode => native.hashCode;
 
   /// The abbreviated time zone name&mdash;for example,
   /// [:"CET":] or [:"CEST":].