message: don't include value length in routing key
diff: @@ -132,7 +132,10 @@ fn serialize_routing_key_with_indexes(
  0 => None,
  1 => values
  .get(pk_indexes[0] as usize)
  - .map(|value| value.serialize_to_vec(version)),
  + .and_then(|value| match value {
  + Value::Some(value) => Some(value.serialize_to_vec(version)),
  + _ => None,
  + }),
  _ => {
  let mut buf = vec![];
  if pk_indexes
  