reduce calls to offlinestorage while uploading attachments using debounce

packages/stream_chat/lib/src/api/channel.dart

@@ -7,6 +7,7 @@ import 'package:dio/dio.dart';
 import 'package:logging/logging.dart';
 import 'package:rxdart/rxdart.dart';
 import 'package:stream_chat/src/api/retry_queue.dart';
+import 'package:stream_chat/src/debounce.dart';
 import 'package:stream_chat/src/event_type.dart';
 import 'package:stream_chat/src/models/attachment_file.dart';
 import 'package:stream_chat/src/models/channel_state.dart';
@@ -1685,7 +1686,11 @@ class ChannelClientState {
 
   set _channelState(ChannelState v) {
     _channelStateController.add(v);
-    _channel._client.chatPersistenceClient?.updateChannelState(v);
+    debounce(
+      timeout: Duration(milliseconds: 500),
+      target: _channel._client.chatPersistenceClient?.updateChannelState,
+      arguments: [v],
+    );
   }
 
   /// The channel threads related to this channel

packages/stream_chat/lib/src/debounce.dart

@@ -0,0 +1,23 @@
+import 'dart:async';
+
+import 'package:meta/meta.dart';
+
+/// Map of timeouts being debounced
+Map timeouts = {};
+
+/// Runs a function avoiding calling it too many times in a [timeoutMS] window
+void debounce({
+  @required Duration timeout,
+  @required Function target,
+  @required List arguments,
+}) {
+  if (timeouts.containsKey(target)) {
+    timeouts[target].cancel();
+  }
+
+  final timer = Timer(timeout, () {
+    Function.apply(target, arguments);
+  });
+
+  timeouts[target] = timer;
+}