fallback utf8 instead latin when charset missing

app/lib/extensions/http_encoding.dart

@@ -0,0 +1,39 @@
+import 'dart:convert';
+
+import 'package:http/http.dart';
+import 'package:http_parser/http_parser.dart';
+
+/// This is modified from default latin1 fallback to use utf8
+Encoding _encodingForHeaders(Map<String, String> headers) =>
+    _encodingForContentTypeHeader(_contentTypeForHeaders(headers), utf8);
+
+/// Returns the [MediaType] object for the given headers' content-type.
+///
+/// Defaults to `application/octet-stream`.
+MediaType _contentTypeForHeaders(Map<String, String> headers) {
+  final contentType = headers['content-type'];
+  if (contentType != null) return MediaType.parse(contentType);
+  return MediaType('application', 'octet-stream');
+}
+
+Encoding _encodingForContentTypeHeader(
+  MediaType contentTypeHeader, [
+  Encoding fallback = latin1,
+]) {
+  final charset = contentTypeHeader.parameters['charset'];
+
+  // Default to utf8 for application/json when charset is unspecified.
+  if (contentTypeHeader.type == 'application' &&
+      contentTypeHeader.subtype == 'json' &&
+      charset == null) {
+    return utf8;
+  }
+
+  // Attempt to find the encoding or fall back to the default.
+  return charset != null ? Encoding.getByName(charset) ?? fallback : fallback;
+}
+
+extension ResponesEncoding on Response {
+  String get bodyUnicodeFallback =>
+      _encodingForHeaders(headers).decode(bodyBytes);
+}