add comments

aws-s3-transfer-manager/src/io/aggregated_bytes.rs

@@ -11,7 +11,6 @@ use bytes_utils::SegmentedBuf;
 
 use crate::error::ErrorKind;
 
-///
 /// Non-contiguous Binary Data Storage
 ///
 /// When data is read from the network, it is read in a sequence of chunks that are not in

aws-s3-transfer-manager/src/operation/download/handle.rs

@@ -69,6 +69,8 @@ impl DownloadHandle {
         self.body.close();
 
         self.discovery.await??;
+        // It's safe to grab the lock here because discovery is already complete, and we will never
+        // lock tasks again after discovery to spawn more tasks.
         let mut tasks = self.tasks.lock().await;
         while let Some(join_result) = tasks.join_next().await {
             join_result?;