fix: padding data type and build instructions for kotlin

examples/android-kotlin/README.md

@@ -20,7 +20,7 @@ export ANDROID_HOME=/path/to/android/sdk/
 make mobile-android
 
 # Copy the jar into `libs/` folder
-cp ./build/lib/gowaku.jar ./examples/android-kotlin/app/libs/.
+cp ./build/lib/gowaku.aar ./examples/android-kotlin/app/libs/.
 ```
 
 Open the project in Android Studio and run the example app.

examples/android-kotlin/app/src/main/java/com/example/waku/messages/DecodedPayload.kt

@@ -8,5 +8,5 @@ data class DecodedPayload(
     val pubkey: String?,
     val signature: String?,
     @Serializable(with = ByteArrayBase64Serializer::class) val data: ByteArray,
-    val padding: String?
+    @Serializable(with = ByteArrayBase64Serializer::class) val padding: ByteArray,
 )

examples/waku-csharp/waku-csharp/Waku.Node.cs

@@ -33,7 +33,7 @@ namespace Waku
         public string? pubkey { get; set; }
         public string? signature { get; set; }
         public byte[] data { get; set; } = new byte[0];
-        public string? padding { get; set; }
+        public byte[] padding { get; set; } = new byte[0];
     }
 
     public class Peer