Cleanup package:http utils (#1011)

pkgs/http/lib/src/utils.dart

@@ -12,14 +12,11 @@ import 'byte_stream.dart';
 ///
 ///     mapToQuery({"foo": "bar", "baz": "bang"});
 ///     //=> "foo=bar&baz=bang"
-String mapToQuery(Map<String, String> map, {Encoding? encoding}) {
-  var pairs = <List<String>>[];
-  map.forEach((key, value) => pairs.add([
-        Uri.encodeQueryComponent(key, encoding: encoding ?? utf8),
-        Uri.encodeQueryComponent(value, encoding: encoding ?? utf8)
-      ]));
-  return pairs.map((pair) => '${pair[0]}=${pair[1]}').join('&');
-}
+String mapToQuery(Map<String, String> map, {required Encoding encoding}) =>
+    map.entries
+        .map((e) => '${Uri.encodeQueryComponent(e.key, encoding: encoding)}'
+            '=${Uri.encodeQueryComponent(e.value, encoding: encoding)}')
+        .join('&');
 
 /// Returns the [Encoding] that corresponds to [charset].
 ///
@@ -34,8 +31,6 @@ Encoding encodingForCharset(String? charset, [Encoding fallback = latin1]) {
 ///
 /// Throws a [FormatException] if no [Encoding] was found that corresponds to
 /// [charset].
-///
-/// [charset] may not be null.
 Encoding requiredEncodingForCharset(String charset) =>
     Encoding.getByName(charset) ??
     (throw FormatException('Unsupported encoding "$charset".'));
@@ -53,9 +48,8 @@ bool isPlainAscii(String string) => _asciiOnly.hasMatch(string);
 /// If [input] is a [TypedData], this just returns a view on [input].
 Uint8List toUint8List(List<int> input) {
   if (input is Uint8List) return input;
-  if (input is TypedData) {
-    // TODO(nweiz): remove "as" when issue 11080 is fixed.
-    return Uint8List.view((input as TypedData).buffer);
+  if (input case TypedData data) {
+    return Uint8List.view(data.buffer);
   }
   return Uint8List.fromList(input);
 }