Allow overriding defaultCache

@@ -10,6 +10,7 @@
 - Update pdfium library to 4627
 - Update pdfium library to 4627
 - Apply Flutter 2.5 coding style
 - Apply Flutter 2.5 coding style
 - Add WidgetWraper.fromWidget()
 - Add WidgetWraper.fromWidget()
+- Allow overriding defaultCache
 
 
 ## 5.5.0
 ## 5.5.0
 
 

@@ -26,7 +26,7 @@ abstract class PdfBaseCache {
   const PdfBaseCache();
   const PdfBaseCache();
 
 
   /// The default cache used when none specified
   /// The default cache used when none specified
-  static final defaultCache = PdfMemoryCache();
+  static PdfBaseCache defaultCache = PdfMemoryCache();
 
 
   /// Add some data to the cache
   /// Add some data to the cache
   Future<void> add(String key, Uint8List bytes);
   Future<void> add(String key, Uint8List bytes);