Feature/send message by int on port (#824)

* feat: send message by `int` on port

* docs: Update README.md

Author: jackleemeta

README.md

@@ -320,7 +320,7 @@ void initState() {
   IsolateNameServer.registerPortWithName(_port.sendPort, 'downloader_send_port');
   _port.listen((dynamic data) {
     String id = data[0];
-    DownloadTaskStatus status = data[1];
+    DownloadTaskStatus status = DownloadTaskStatus(data[1]);
     int progress = data[2];
     setState((){ });
   });
@@ -335,7 +335,7 @@ void dispose() {
 }
 
 @pragma('vm:entry-point')
-static void downloadCallback(String id, DownloadTaskStatus status, int progress) {
+static void downloadCallback(String id, int status, int progress) {
   final SendPort send = IsolateNameServer.lookupPortByName('downloader_send_port');
   send.send([id, status, progress]);
 }

example/lib/home_page.dart

@@ -90,7 +90,7 @@ class _MyHomePageState extends State<MyHomePage> {
   @pragma('vm:entry-point')
   static void downloadCallback(
     String id,
-    DownloadTaskStatus status,
+    int status,
     int progress,
   ) {
     print(
@@ -99,7 +99,7 @@ class _MyHomePageState extends State<MyHomePage> {
     );
 
     IsolateNameServer.lookupPortByName('downloader_send_port')
-        ?.send([id, status.value, progress]);
+        ?.send([id, status, progress]);
   }
 
   Widget _buildDownloadList() {

lib/src/callback_dispatcher.dart

@@ -4,8 +4,6 @@ import 'dart:ui';
 import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
 
-import 'models.dart';
-
 /// Pragma annotation is needed to avoid tree shaking in release mode. See
 /// https://github.com/dart-lang/sdk/blob/master/runtime/docs/compiler/aot/entry_point_pragma.md
 @pragma('vm:entry-point')
@@ -30,7 +28,7 @@ void callbackDispatcher() {
       final status = args[2] as int;
       final progress = args[3] as int;
 
-      callback(id, DownloadTaskStatus(status), progress);
+      callback(id, status, progress);
     })
     ..invokeMethod<void>('didInitializeDispatcher');
 }

lib/src/downloader.dart

@@ -4,7 +4,6 @@ import 'dart:io';
 import 'dart:ui';
 
 import 'package:flutter/services.dart';
-import 'package:flutter/widgets.dart';
 import 'package:flutter_downloader/src/exceptions.dart';
 
 import 'callback_dispatcher.dart';
@@ -14,7 +13,7 @@ import 'models.dart';
 /// with [id] changes.
 typedef DownloadCallback = void Function(
   String id,
-  DownloadTaskStatus status,
+  int status,
   int progress,
 );
 
@@ -396,7 +395,7 @@ class FlutterDownloader {
   ///  IsolateNameServer.registerPortWithName(_port.sendPort, 'downloader_send_port');
   ///  _port.listen((dynamic data) {
   ///     String id = data[0];
-  ///     DownloadTaskStatus status = data[1];
+  ///     DownloadTaskStatus status = DownloadTaskStatus(data[1]);
   ///     int progress = data[2];
   ///     setState((){ });
   ///  });
@@ -406,7 +405,7 @@ class FlutterDownloader {
   ///
   ///static void downloadCallback(
   ///  String id,
-  ///  DownloadTaskStatus status,
+  ///  int status,
   ///  int progress,
   ///  ) {
   ///    final SendPort send = IsolateNameServer.lookupPortByName(