Add note about iterators

flat_tree/iterator.py

@@ -19,6 +19,10 @@ class FlatTreeIterator:
     def __attrs_post_init__(self):
         self.seek(self.index)
 
+    # TODO(decentral1se): Once we get to the point of actually using this
+    # module in hypercore or wherever it is needed we should consider whether
+    # or not to make this a real Python iterator using the protocol methods of
+    # __iter__ and __next__
     def next(self) -> int:
         """The next index in the tree."""
         self.offset += 1