Prepare for upcoming change to File.openRead()

An upcoming change to the Dart SDK will change the signature
of `File.openRead()` from returning `Stream<List<int>>` to
returning `Stream<Uint8List>`.

This forwards-compatible change prepares for that SDK breaking
change by casting the Stream to `List<int>` before transforming
it.

https://github.com/dart-lang/sdk/issues/36900

lib/src/virtual_directory.dart

@@ -1,4 +1,5 @@
 import 'dart:async';
+import 'dart:typed_data';
 import 'package:angel_framework/angel_framework.dart';
 import 'package:file/file.dart';
 import 'package:http_parser/http_parser.dart';
@@ -284,7 +285,7 @@ class VirtualDirectory {
             statusCode: 416, message: '`Range` header may not be empty.');
       } else if (header.items.length == 1) {
         var item = header.items[0];
-        Stream<List<int>> stream;
+        Stream<Uint8List> stream;
         int len = 0, total = totalFileSize;
 
         if (item.start == -1) {
@@ -311,7 +312,7 @@ class VirtualDirectory {
         res.statusCode = 206;
         res.headers['content-length'] = len.toString();
         res.headers['content-range'] = 'bytes ' + item.toContentRange(total);
-        await stream.pipe(res);
+        await stream.cast<List<int>>().pipe(res);
         return false;
       } else {
         var transformer = RangeHeaderTransformer(
@@ -324,7 +325,11 @@ class VirtualDirectory {
             transformer.computeContentLength(totalFileSize).toString();
         res.contentType = MediaType(
             'multipart', 'byteranges', {'boundary': transformer.boundary});
-        await file.openRead().transform(transformer).pipe(res);
+        await file
+            .openRead()
+            .cast<List<int>>()
+            .transform(transformer)
+            .pipe(res);
         return false;
       }
     }

pubspec.yaml

@@ -4,7 +4,7 @@ environment:
   sdk: ">=2.0.0 <3.0.0"
 homepage: https://github.com/angel-dart/static
 author: Tobe O <thosakwe@gmail.com>
-version: 2.1.3+1
+version: 2.1.3+2
 dependencies:
   angel_framework: ^2.0.0-rc.0
   convert: ^2.0.0