Did a flutter upgrade and receive this error.

[robertjones26]

/C:/Users/rwjon/AppData/Local/Pub/Cache/hosted/pub.dev/super_native_extensions-0.8.19/lib/src/native/drag.dart(4,8): error GBB7C8005: Error when reading '/C:/Users/rwjon/AppData/Local/Pub/Cache/hosted/pub.dev/irondash_engine_context-0.5.4/lib/irondash_engine_context.dart': The system cannot find the path specified. [C:\pinogy\bit\flutter_apps\pos_app\build\windows\x64\flutter\flutter_assemble.vcxproj]
/C:/Users/rwjon/AppData/Local/Pub/Cache/hosted/pub.dev/super_native_extensions-0.8.19/lib/src/native/drop.dart(2,8): error GBB7C8005: Error when reading '/C:/Users/rwjon/AppData/Local/Pub/Cache/hosted/pub.dev/irondash_engine_context-0.5.4/lib/irondash_engine_context.dart': The system cannot find the path specified. [C:\pinogy\bit\flutter_apps\pos_app\build\windows\x64\flutter\flutter_assemble.vcxproj]
/C:/Users/rwjon/AppData/Local/Pub/Cache/hosted/pub.dev/super_native_extensions-0.8.19/lib/src/native/menu.dart(6,8): error GBB7C8005: Error when reading '/C:/Users/rwjon/AppData/Local/Pub/Cache/hosted/pub.dev/irondash_engine_context-0.5.4/lib/irondash_engine_context.dart': The system cannot find the path specified. [C:\pinogy\bit\flutter_apps\pos_app\build\windows\x64\flutter\flutter_assemble.vcxproj]
/C:/Users/rwjon/AppData/Local/Pub/Cache/hosted/pub.dev/super_native_extensions-0.8.19/lib/src/native/drag.dart(96,32): error GD65BB2B6: The getter 'EngineContext' isn't defined for the class 'DragContextImpl'. [C:\pinogy\bit\flutter_apps\pos_app\build\windows\x64\flutter\flutter_assemble.vcxproj]
/C:/Users/rwjon/AppData/Local/Pub/Cache/hosted/pub.dev/super_native_extensions-0.8.19/lib/src/native/drop.dart(117,32): error GD65BB2B6: The getter 'EngineContext' isn't defined for the class 'DropContextImpl'. [C:\pinogy\bit\flutter_apps\pos_app\build\windows\x64\flutter\flutter_assemble.vcxproj]
/C:/Users/rwjon/AppData/Local/Pub/Cache/hosted/pub.dev/super_native_extensions-0.8.19/lib/src/native/menu.dart(178,32): error GD65BB2B6: The getter 'EngineContext' isn't defined for the class 'MenuContextImpl'. [C:\pinogy\bit\flutter_apps\pos_app\build\windows\x64\flutter\flutter_assemble.vcxproj]
C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Microsoft\VC\v160\Microsoft.CppCommon.targets(240,5): error MSB8066: Custom build for 'C:\pinogy\bit\flutter_apps\pos_app\build\windows\x64\CMakeFiles\ecbb5a7bb849423a741cf8198534a981\flutter_windows.dll.rule;C:\pinogy\bit\flutter_apps\pos_app\build\windows\x64\CMakeFiles\e3a9b599db424e24f5d3dc21a39bd8c8\flutter_assemble.rule' exited with code 1. [C:\pinogy\bit\flutter_apps\pos_app\build\windows\x64\flutter\flutter_assemble.vcxproj]

[knopp]

'/C:/Users/rwjon/AppData/Local/Pub/Cache/hosted/pub.dev/irondash_engine_context-0.5.4/lib/irondash_engine_context.dart': The system cannot find the path specified.

There is something wrong with your pub cache, the files are missing. I'm not sure what caused this but I don't think it is directly related to super_native_extensions.