Add test binned json

items_0/src/collect_s.rs

@@ -49,7 +49,7 @@ impl ToJsonBytes for serde_json::Value {
     }
 }
 
-pub trait Collected: fmt::Debug + ToJsonResult + AsAnyRef + Send {}
+pub trait Collected: fmt::Debug + Send + AsAnyRef + WithLen + ToJsonResult {}
 
 erased_serde::serialize_trait_object!(Collected);
 
@@ -59,6 +59,12 @@ impl ToJsonResult for Box<dyn Collected> {
     }
 }
 
+impl WithLen for Box<dyn Collected> {
+    fn len(&self) -> usize {
+        self.as_ref().len()
+    }
+}
+
 impl Collected for Box<dyn Collected> {}
 
 // TODO rename to `Typed`