stop rdf parsing at rdf:RDF tag

lib/feed_reader/formats/rdf.ex

@@ -21,6 +21,7 @@ defmodule FeedReader.Formats.RDF do
       limits: XMLResourceLimits.new(opts),
       frames: [],
       channel: nil,
+      root_closed: false,
       error: nil
     }
 

lib/feed_reader/formats/rdf/handler.ex

@@ -96,5 +96,6 @@ defmodule FeedReader.Formats.RDF.Handler do
     {:ok, %{state | frames: [%{parent | children: children} | rest]}}
   end
 
-  defp close_element(_frame, _value, state), do: {:ok, state}
+  defp close_element(_frame, _value, %{frames: []} = state),
+    do: {:halt, %{state | root_closed: true}}
 end