add usernameBuilder param

packages/stream_chat_flutter/lib/src/message_actions_modal.dart

@@ -35,6 +35,7 @@ class MessageActionsModal extends StatefulWidget {
     this.customActions = const [],
     this.attachmentBorderRadiusGeometry,
     this.onCopyTap,
+    this.textBuilder,
   }) : super(key: key);
 
   /// Builder for edit message
@@ -97,6 +98,9 @@ class MessageActionsModal extends StatefulWidget {
   /// List of custom actions
   final List<MessageAction> customActions;
 
+  /// Customize the MessageWidget textBuilder
+  final Widget Function(BuildContext context, Message message)? textBuilder;
+
   @override
   _MessageActionsModalState createState() => _MessageActionsModalState();
 }
@@ -222,6 +226,7 @@ class _MessageActionsModalState extends State<MessageActionsModal> {
                               showSendingIndicator: false,
                               shape: widget.messageShape,
                               attachmentShape: widget.attachmentShape,
+                              textBuilder: widget.textBuilder,
                             ),
                           ),
                           const SizedBox(height: 8),

packages/stream_chat_flutter/lib/src/message_list_view.dart

@@ -156,8 +156,9 @@ class MessageListView extends StatefulWidget {
     this.onMessageTap,
     this.onSystemMessageTap,
     this.onAttachmentTap,
-    this.textBuilder,
     this.onLinkTap,
+    this.textBuilder,
+    this.usernameBuilder,
   }) : super(key: key);
 
   /// Function used to build a custom message widget
@@ -259,7 +260,10 @@ class MessageListView extends StatefulWidget {
   final void Function(Message message, Attachment attachment)? onAttachmentTap;
 
   /// Customize the MessageWidget textBuilder
-  final void Function(BuildContext context, Message message)? textBuilder;
+  final Widget Function(BuildContext context, Message message)? textBuilder;
+
+  /// Customize the MessageWidget usernameBuilder
+  final Widget Function(BuildContext context, Message message)? usernameBuilder;
 
   /// Callback for when link is tapped
   final void Function(String link)? onLinkTap;
@@ -857,8 +861,8 @@ class _MessageListViewState extends State<MessageListView> {
         }
         FocusScope.of(context).unfocus();
       },
-      textBuilder:
-          widget.textBuilder as Widget Function(BuildContext, Message)?,
+      textBuilder: widget.textBuilder,
+      usernameBuilder: widget.usernameBuilder,
       onLinkTap: widget.onLinkTap,
     );
   }
@@ -1056,8 +1060,8 @@ class _MessageListViewState extends State<MessageListView> {
         FocusScope.of(context).unfocus();
       },
       onAttachmentTap: widget.onAttachmentTap,
-      textBuilder:
-          widget.textBuilder as Widget Function(BuildContext, Message)?,
+      textBuilder: widget.textBuilder,
+      usernameBuilder: widget.usernameBuilder,
       onLinkTap: widget.onLinkTap,
     );
 

packages/stream_chat_flutter/lib/src/message_reactions_modal.dart

@@ -23,6 +23,7 @@ class MessageReactionsModal extends StatelessWidget {
     this.showUserAvatar = DisplayWidget.show,
     this.onUserAvatarTap,
     this.attachmentBorderRadiusGeometry,
+    this.textBuilder,
   }) : super(key: key);
 
   /// Message to display reactions of
@@ -52,6 +53,9 @@ class MessageReactionsModal extends StatelessWidget {
   /// [BorderRadius] to apply to attachments
   final BorderRadius? attachmentBorderRadiusGeometry;
 
+  /// Customize the MessageWidget textBuilder
+  final Widget Function(BuildContext context, Message message)? textBuilder;
+
   @override
   Widget build(BuildContext context) {
     final size = MediaQuery.of(context).size;
@@ -157,6 +161,7 @@ class MessageReactionsModal extends StatelessWidget {
                               ),
                               showReactionPickerIndicator: showReactions &&
                                   (message.status == MessageSendingStatus.sent),
+                              textBuilder: textBuilder,
                             ),
                           ),
                           if (message.latestReactions?.isNotEmpty == true) ...[

packages/stream_chat_flutter/lib/src/message_widget.dart

@@ -102,6 +102,7 @@ class MessageWidget extends StatefulWidget {
     this.onQuotedMessageTap,
     this.customActions = const [],
     this.onAttachmentTap,
+    this.usernameBuilder,
   })  : attachmentBuilders = {
           'image': (context, message, attachments) {
             final border = RoundedRectangleBorder(
@@ -265,6 +266,9 @@ class MessageWidget extends StatefulWidget {
   /// Widget builder for building text
   final Widget Function(BuildContext, Message)? textBuilder;
 
+  /// Widget builder for building username
+  final Widget Function(BuildContext, Message)? usernameBuilder;
+
   /// Function called on long press
   final void Function(BuildContext, Message)? onMessageActions;
 
@@ -721,14 +725,7 @@ class _MessageWidgetState extends State<MessageWidget>
           child: Text(msg, style: widget.messageTheme.replies),
         ),
       ],
-      if (showUsername)
-        Text(
-          widget.message.user!.name,
-          maxLines: 1,
-          key: usernameKey,
-          style: widget.messageTheme.messageAuthor,
-          overflow: TextOverflow.ellipsis,
-        ),
+      if (showUsername) _buildUsername(usernameKey),
       if (showTimeStamp)
         Text(
           Jiffy(widget.message.createdAt.toLocal()).jm,
@@ -791,6 +788,19 @@ class _MessageWidgetState extends State<MessageWidget>
     );
   }
 
+  Widget _buildUsername(Key usernameKey) {
+    if (widget.usernameBuilder != null) {
+      return widget.usernameBuilder!(context, widget.message);
+    }
+    return Text(
+      widget.message.user!.name,
+      maxLines: 1,
+      key: usernameKey,
+      style: widget.messageTheme.messageAuthor,
+      overflow: TextOverflow.ellipsis,
+    );
+  }
+
   Widget _buildUrlAttachment() {
     final urlAttachment = widget.message.attachments
         .firstWhere((element) => element.ogScrapeUrl != null);
@@ -882,6 +892,7 @@ class _MessageWidgetState extends State<MessageWidget>
         builder: (context) => StreamChannel(
               channel: channel,
               child: MessageActionsModal(
+                textBuilder: widget.textBuilder,
                 onCopyTap: (message) =>
                     Clipboard.setData(ClipboardData(text: message.text)),
                 attachmentBorderRadiusGeometry:
@@ -931,6 +942,7 @@ class _MessageWidgetState extends State<MessageWidget>
       builder: (context) => StreamChannel(
         channel: channel,
         child: MessageReactionsModal(
+          textBuilder: widget.textBuilder,
           attachmentBorderRadiusGeometry:
               widget.attachmentBorderRadiusGeometry as BorderRadius?,
           showUserAvatar: