Migrate away from deprecated strong-mode analysis options

Author: parlough

analysis_options.yaml

@@ -1,9 +1,10 @@
 include: package:flutter_lints/flutter.yaml
 
 analyzer:
-  strong-mode:
-    implicit-casts: false
-    implicit-dynamic: false
+  language:
+    # strict-casts: true -- DISABLED: Enabled in Dart 2.17
+    strict-inference: true
+    strict-raw-types: true
   exclude:
     - "bin/cache/**"
     - "**/*.freezed.dart"

packages/flutter_reactive_ble/lib/src/rx_ext/serial_disposable.dart

@@ -40,11 +40,11 @@ class _SerialAlreadyDisposed extends Error {
   String toString() => "An instance of $_type has already been disposed";
 }
 
-/// A [SerialDisposable] that constains an underlying stream subscription.
-class StreamSubscriptionSerialDisposable
-    extends SerialDisposable<StreamSubscription> {
+/// A [SerialDisposable] that contains an underlying stream subscription.
+class StreamSubscriptionSerialDisposable<T>
+    extends SerialDisposable<StreamSubscription<T>> {
   StreamSubscriptionSerialDisposable()
-      : super((StreamSubscription subscription) async {
+      : super((StreamSubscription<T> subscription) async {
           await subscription.cancel();
           return const Unit();
         });