[StreamChatCore] Move EventHandler into typedef.dart

Signed-off-by: Sahil Kumar <[email protected]>

packages/stream_chat_flutter_core/lib/src/stream_chat_core.dart

@@ -4,7 +4,7 @@ import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:stream_chat/stream_chat.dart';
 
-typedef EventHandler = void Function(Event event);
+import 'typedef.dart';
 
 /// Widget used to provide information about the chat to the widget tree.
 /// This Widget is used to react to life cycle changes and system updates.

packages/stream_chat_flutter_core/lib/src/typedef.dart

@@ -1,6 +1,10 @@
 import 'package:flutter/widgets.dart';
+import 'package:stream_chat/stream_chat.dart';
 
 /// A signature for a callback which exposes an error and returns a function.
 /// This Callback can be used in cases where an API failure occurs and the widget
 /// is unable to render data.
 typedef ErrorBuilder = Widget Function(BuildContext context, Object error);
+
+/// A Signature for a handler function which will expose a [event].
+typedef EventHandler = void Function(Event event);