Have fastavro log on deserialization failures (#1058)

Co-authored-by: captain-kark <[email protected]>

Author: Matt Howlett

src/confluent_kafka/avro/serializer/message_serializer.py

@@ -189,8 +189,7 @@ def _get_decoder_func(self, schema_id, payload, is_key=False):
                     p, fast_avro_writer_schema, fast_avro_reader_schema)
                 return self.id_to_decoder_func[schema_id]
             except Exception:
-                # Fast avro failed, fall thru to standard avro below.
-                pass
+                log.warning("Fast avro failed for schema with id %d, falling thru to standard avro" % (schema_id))
 
         # here means we should just delegate to slow avro
         # rewind