Added proguard rules for kotlinx.serialization

app/proguard-rules.pro

@@ -0,0 +1,23 @@
+# Keep `Companion` object fields of serializable classes.
+# This avoids serializer lookup through `getDeclaredClasses` as done for named companion objects.
+-if @kotlinx.serialization.Serializable class **
+-keepclassmembers class <1> {
+    static <1>$Companion Companion;
+}
+
+# Keep `serializer()` on companion objects (both default and named) of serializable classes.
+-if @kotlinx.serialization.Serializable class ** {
+    static **$* *;
+}
+-keepclassmembers class <2>$<3> {
+    kotlinx.serialization.KSerializer serializer(...);
+}
+
+# Keep `INSTANCE.serializer()` of serializable objects.
+-if @kotlinx.serialization.Serializable class ** {
+    public static ** INSTANCE;
+}
+-keepclassmembers class <1> {
+    public static <1> INSTANCE;
+    kotlinx.serialization.KSerializer serializer(...);
+}