add doc to BatchHandler
@@ -28,6 +28,9 @@ pub trait BatchHandler: Sync + Send + 'static {
fn accept(&self, batch: &Batch) -> bool;
/// Processes the `Task` batch returning the batch with the `Task` updated.
+ ///
+ /// It is ok for this function to panic if a batch is handed that hasn't been verified by
+ /// `accept` beforehand.
async fn process_batch(&self, batch: Batch) -> Batch;
/// `finish` is called when the result of `process` has been commited to the task store. This
