custom_app_bar_trial_2.dart

// Inside the build() method of our ChatRoom() widget
return Scaffold(
      backgroundColor: Color(0xFFECE5DD),
      appBar: AppBar(
        title: SizedBox(
          width: double.infinity,
          child: Stack(
            overflow: Overflow.visible,
            children: <Widget>[
              Positioned(
                left: leftOffset,
                top: defaultIconButtonPadding,
                child: CircleAvatar(
                  radius: avatarRadius,
                  child: chatItem.avatar,
                ),
              ),
              Positioned(
                left: leftOffset + avatarRadius * 2 + 8.0,
                top: defaultIconButtonPadding +
                    avatarRadius / 2 -
                    titleLineHeight,
                child: Text(chatItem.name),
              ),
            ],      
     // ...below remains the same