diff --git a/src/stream.rs b/src/stream.rs
index 7b32a7c..d649d8e 100644
--- a/src/stream.rs
+++ b/src/stream.rs
@@ -209,6 +209,7 @@ pub fn build_formatted_output_stream(cfg: &Stream, stream: Box<dyn OutputStream>
    });
 }
 
+// TODO use https://crates.io/crates/handlebars instead
 impl OutputStream for OutputStreamFormatted {
    fn put(&mut self, v: Vec<char>) {
       match self.format.as_ref() {