chore: add toString method in ChannelStateChange class for improved debugging

lib/src/main/java/io/ably/lib/realtime/ChannelStateListener.java

@@ -1,6 +1,7 @@
 package io.ably.lib.realtime;
 
 import io.ably.lib.types.ErrorInfo;
+import org.jetbrains.annotations.NotNull;
 
 /**
  * An interface whereby a client may be notified of state changes for a channel.
@@ -69,6 +70,17 @@ private ChannelStateChange(ErrorInfo reason, boolean resumed) {
         static ChannelStateChange createUpdateEvent(ErrorInfo reason, boolean resumed) {
             return new ChannelStateChange(reason, resumed);
         }
+
+        @Override
+        public @NotNull String toString() {
+            return '{' +
+                "event=" + event +
+                ", current=" + current +
+                ", previous=" + previous +
+                ", reason=" + reason +
+                ", resumed=" + resumed +
+                '}';
+        }
     }
 
     class Multicaster extends io.ably.lib.util.Multicaster<ChannelStateListener> implements ChannelStateListener {

lib/src/main/java/io/ably/lib/types/Annotation.java

@@ -10,6 +10,7 @@
 import com.google.gson.JsonSerializer;
 import io.ably.lib.util.Log;
 import io.ably.lib.util.Serialisation;
+import org.jetbrains.annotations.NotNull;
 import org.msgpack.core.MessageFormat;
 import org.msgpack.core.MessagePacker;
 import org.msgpack.core.MessageUnpacker;
@@ -233,6 +234,22 @@ public Annotation deserialize(JsonElement json, Type typeOfT, JsonDeserializatio
         }
     }
 
+    /**
+     * Generate a String summary of this Message
+     * @return string
+     */
+    @Override
+    public @NotNull String toString() {
+        StringBuilder result = new StringBuilder("{");
+        super.getDetails(result);
+        result.append(" name=").append(name);
+        result.append(" serial=").append(serial);
+        result.append(" messageSerial=").append(messageSerial);
+        result.append(" type=").append(type);
+        result.append('}');
+        return result.toString();
+    }
+
     public static class ActionSerializer implements JsonSerializer<AnnotationAction>, JsonDeserializer<AnnotationAction> {
         @Override
         public AnnotationAction deserialize(JsonElement json, Type t, JsonDeserializationContext ctx)