use gomuks for downloading media

lib/helpers/mxc_image.dart

@@ -0,0 +1,35 @@
+import "dart:ui";
+import "package:flutter/widgets.dart";
+import "package:flutter_riverpod/flutter_riverpod.dart";
+import "package:nexus/controllers/client.dart";
+import "package:nexus/models/requests/download_media.dart";
+
+class MxcImage extends ImageProvider<MxcImage> {
+  final WidgetRef ref;
+  final DownloadMediaRequest request;
+  const MxcImage(this.ref, this.request);
+
+  @override
+  Future<MxcImage> obtainKey(ImageConfiguration configuration) =>
+      Future.value(this);
+
+  @override
+  ImageStreamCompleter loadImage(MxcImage key, ImageDecoderCallback decode) =>
+      MultiFrameImageStreamCompleter(codec: _loadAsync(decode), scale: 1.0);
+
+  Future<Codec> _loadAsync(ImageDecoderCallback decode) async {
+    final file = await ref
+        .read(ClientController.provider.notifier)
+        .downloadMedia(request);
+    final buffer = await ImmutableBuffer.fromFilePath(file.path);
+
+    return decode(buffer);
+  }
+
+  @override
+  bool operator ==(Object other) =>
+      other is MxcImage && other.request == request;
+
+  @override
+  int get hashCode => request.hashCode;
+}