Add todo comment.

src/githubctl/github_endpoint_watcher.rs

@@ -41,6 +41,10 @@ impl GithubEndpointWatcher {
     pub async fn skip_results_before_now(&mut self) -> Result<(), Box<dyn std::error::Error>> {
         // This will incur an API call to get the headers for ETAG and
         // last modified at but it will throw away the results.
+
+        // TODO: Can this be done without a request? We wouldn't get
+        // an ETAG but we should be able to calculate our own date
+        // string for last modified.
         let request = self.build_request()?;
         self.sleep_until_next_poll().await?;
         self.sleep_until_ratelimit().await?;