fix!: Cache should take key to be properly cleared

packages/audioplayers/lib/src/audio_cache.dart

@@ -32,7 +32,7 @@ class AudioCache {
   /// On mobile/desktop, the URIs are from local files where the bytes have been
   /// copied.
   /// On web, the URIs are external links for pre-loaded files.
-  Map<String, Uri> loadedFiles = {};
+  final Map<String, Uri> loadedFiles = {};
 
   /// This is the path inside your assets folder where your files lie.
   ///
@@ -50,7 +50,7 @@ class AudioCache {
   /// Does nothing if the file was not on cache.
   /// Note: web relies on the browser cache which is handled entirely by the
   /// browser, thus this will no-op.
-  Future<void> clear(Uri fileName) async {
+  Future<void> clear(String fileName) async {
     final uri = loadedFiles.remove(fileName);
     if (uri != null && !kIsWeb) {
       await File(uri.toFilePath()).delete();
@@ -59,7 +59,7 @@ class AudioCache {
 
   /// Clears the whole cache.
   Future<void> clearAll() async {
-    await Future.wait(loadedFiles.values.map(clear));
+    await Future.wait(loadedFiles.keys.map(clear));
   }
 
   Future<Uri> fetchToMemory(String fileName) async {

packages/audioplayers/test/audio_cache_test.dart

@@ -34,5 +34,17 @@ void main() {
       await player.load('audio.mp3');
       expect(player.called, hasLength(0));
     });
+
+    test('clear cache', () async {
+      final player = MyAudioCache();
+      await player.load('audio.mp3');
+      expect(player.loadedFiles['audio.mp3'], isNotNull);
+      player.clearAll();
+      expect(player.loadedFiles, <String, Uri>{});
+      await player.load('audio.mp3');
+      expect(player.loadedFiles.isNotEmpty, isTrue);
+      player.clear('audio.mp3');
+      expect(player.loadedFiles, <String, Uri>{});
+    });
   });
 }