fixup! BOLT01: add wire TLV proposal

01-messaging.md

@@ -136,7 +136,16 @@ field, the node is forced to add parsing logic for that field in order to
 determine the offset of any fields that follow.
 
 The monotonicity constraint ensures that all `type`s are unique and can appear
-at most once.
+at most once. Fields that need which to have multiple occurrences of some
+primitive type or object, e.g. vectors or maps, may do so by defining the
+encoding such that they are all serialized within a single `tlv_record`. The
+uniqueness constraint, among other things, enables the following optimizations:
+ - canonical ordering is defined independent of the encoded `value`s.
+ - canonical ordering can be known at compile-time, rather that being determined
+   dynamically at the time of encoding.
+ - verifying canonical ordering requires less state and is cheaper.
+ - variable-size fields can reserve their expected size up front, rather than
+   appending elements sequentially and incurring double-and-copy overhead.
 
 The use of a varint for `length` permits a space savings over a fixed 16-bit
 `length` for `value`s whose encoded length is less than 253 bytes. When