diff --git a/restic_compose_backup/restic.py b/restic_compose_backup/restic.py
index 030ec9c..4f84e53 100644
--- a/restic_compose_backup/restic.py
+++ b/restic_compose_backup/restic.py
@@ -40,6 +40,9 @@ def backup_from_stdin(repository: str, filename: str, source_command: List[str])
     ])
 
     # pipe source command into dest command
+    # NOTE: Using the default buffer size: io.DEFAULT_BUFFER_SIZE = 8192
+    #       We might want to tweak that to speed up large dumps.
+    #       Actual tests tests must be done.
     source_process = Popen(source_command, stdout=PIPE)
     dest_process = Popen(dest_command, stdin=source_process.stdout, stdout=PIPE, stderr=PIPE)
     stdout, stderr = dest_process.communicate()