feat: add setKey variant, setRawKey (#482)

Author: td-famedly

lib/src/e2ee/key_provider.dart

@@ -40,6 +40,7 @@ abstract class KeyProvider {
   Future<Uint8List> ratchetSharedKey({int? keyIndex});
   Future<Uint8List> exportSharedKey({int? keyIndex});
   Future<void> setKey(String key, {String? participantId, int? keyIndex});
+  Future<void> setRawKey(Uint8List key, {String? participantId, int? keyIndex});
   Future<Uint8List> ratchetKey(String participantId, int? keyIndex);
   Future<Uint8List> exportKey(String participantId, int? keyIndex);
   Future<void> setSifTrailer(Uint8List trailer);
@@ -131,6 +132,13 @@ class BaseKeyProvider implements KeyProvider {
     return _setKey(keyInfo);
   }
 
+  @override
+  Future<void> setRawKey(Uint8List key,
+      {String? participantId, int? keyIndex}) async {
+    return setKey(String.fromCharCodes(key),
+        participantId: participantId, keyIndex: keyIndex);
+  }
+
   Future<void> _setKey(KeyInfo keyInfo) async {
     if (!_keys.containsKey(keyInfo.participantId)) {
       _keys[keyInfo.participantId] = {};