fix

com.unity.uiwidgets/Runtime/engine2/AndroidPlatformUtil.cs

             }
 
             return dir + file;
-
-            return "";
         }
         
         [DllImport(NativeBindings.dllName)]
-            if (Application.platform == RuntimePlatform.Android) {
-                InitUnpackFile(unpackFile);
-                GL.IssuePluginEvent(GetUnityContextEventFunc(), 1);
-            }
+            InitUnpackFile(unpackFile);
+            GL.IssuePluginEvent(GetUnityContextEventFunc(), 1);
         }
     }
 }

engine/README.md

 ```
 
 
-## build android sdk on mac
+## How to Build (Android)
 ### Build flutter fml + skia + txt
 
 1. Setting up the Engine development environment

engine/src/flow/raster_cache.cc

   SkIRect bounds =
       RasterCache::GetDeviceBounds(logical_rect_, canvas.getTotalMatrix());
   FML_DCHECK(
-        Math_abs(bounds.size().width() - image_->dimensions().width()) <= 1 &&
-        Math_abs(bounds.size().height() - image_->dimensions().height()) <= 1);
+      Math_abs(bounds.size().width() - image_->dimensions().width()) <= 1 &&
+      Math_abs(bounds.size().height() - image_->dimensions().height()) <= 1);
   canvas.resetMatrix();
   canvas.drawImage(image_, bounds.fLeft, bounds.fTop, paint);
 }