Re-add comment about json_format.ParseDict

Author: holtskinner

src/a2a/utils/proto_utils.py

@@ -27,6 +27,10 @@
 def dict_to_struct(dictionary: dict[str, Any]) -> struct_pb2.Struct:
     """Converts a Python dict to a Struct proto.
 
+    Unfortunately, using `json_format.ParseDict` does not work because this
+    wants the dictionary to be an exact match of the Struct proto with fields
+    and keys and values, not the traditional Python dict structure.
+
     Args:
       dictionary: The Python dict to convert.