Fix Flutter Bluetooth Printer Bug -- 2

I already have Bluetooth printing code in my Flutter app, yet nothing reaches the thermal printer on either Android or iOS. I need a focused bug-fix that:

• Reviews the current Dart logic and any platform channels I’ve set up for printing.
• Identifies why the printer is not receiving data or failing to render it correctly.
• Implements a concise fix so the printer reliably produces output from both Android and iOS builds.

I’ll provide the existing repository and the printer model details as soon as we start. A short explanation of what was wrong and the lines you changed will help me merge the patch quickly.