Added #toString methods to Resource implementations

httpclient5-cache/src/main/java/org/apache/hc/client5/http/impl/cache/FileResource.java

@@ -109,4 +109,12 @@ public class FileResource extends Resource {
         }
     }
 
+    @Override
+    public String toString() {
+        return "[" +
+                "file=" + getFile() + "," +
+                "len=" + length() +
+                ']';
+    }
+
 }

httpclient5-cache/src/main/java/org/apache/hc/client5/http/impl/cache/HeapResource.java

@@ -74,4 +74,12 @@ public class HeapResource extends Resource {
         this.arrayRef.set(null);
     }
 
+    @Override
+    public String toString() {
+        return "[" +
+                "heap," +
+                "len=" + length() +
+                ']';
+    }
+
 }