Make package strong, also add analysis options file (flutter#4)

* Make package strong, also add analysis options file

* Update analysis_options.yaml

* Update web_socket_handler.dart

* Update pubspec.yaml

* Update web_socket_handler.dart

Author: keertip

analysis_options.yaml

@@ -0,0 +1,2 @@
+analyzer:
+  strong-mode: true

lib/src/web_socket_handler.dart

@@ -5,7 +5,6 @@
 import 'dart:convert';
 
 import 'package:shelf/shelf.dart';
-import 'package:stream_channel/stream_channel.dart';
 import 'package:web_socket_channel/web_socket_channel.dart';
 
 /// A class that exposes a handler for upgrading WebSocket requests.
@@ -65,9 +64,7 @@ class WebSocketHandler {
     }
 
     var protocol = _chooseProtocol(request);
-    request.hijack((untypedChannel) {
-      var channel = (untypedChannel as StreamChannel).cast<List<int>>();
-
+    request.hijack((channel) {
       var sink = UTF8.encoder.startChunkedConversion(channel.sink);
       sink.add(
           "HTTP/1.1 101 Switching Protocols\r\n"

pubspec.yaml

@@ -5,7 +5,7 @@ homepage: http://github.com/dart-lang/shelf_web_socket
 description: >
   A WebSocket handler for Shelf.
 dependencies:
-  shelf: ">=0.6.5 <0.8.0"
+  shelf: ">=0.7.0 <0.8.0"
   stream_channel: "^1.4.0"
   web_socket_channel: "^1.0.0"
 dev_dependencies: