add function to get recorded keys from proof recorder instance

substrate/primitives/trie/src/recorder.rs

@@ -105,6 +105,15 @@ impl<H: Hasher> Clone for Recorder<H> {
 }
 
 impl<H: Hasher> Recorder<H> {
+	/// Keys for which we have recorded the trie nodes till now.
+	/// Note that this does not modify the internals, rather returns snapshot of the recorded keys.
+	/// There can be multiple storage root in case we are tracking more than one tries.
+	pub fn recorded_keys(&self) -> HashMap<<H as Hasher>::Out, HashMap<Arc<[u8]>, RecordedForKey>> {
+		let inner = self.inner.lock();
+		inner.recorded_keys.clone()
+	}
+
+
 	/// Returns the recorder as [`TrieRecorder`](trie_db::TrieRecorder) compatible type.
 	///
 	/// - `storage_root`: The storage root of the trie for which accesses are recorded. This is