v0.1005.0

v0.1005.0

Breaking changes

• The (unstable) internal encoding traits continue to evolve, this time to
  support prepend-encoding.

New features

• Added prepend-encoding: messages can be encoded to a prepend-only buffer, with
  .prepend(reverse_buf) or .encode_fast(). This encoding method writes
  messages in reverse, avoiding any need to "look ahead" in order to encode the
  correct length for data that is not yet written. This enables writing an
  arbitrarily nested message without visiting any field more than once, removing
  a quadratic hazard and general inefficiency in the encoding path.
• New reserved_tags attribute on messages to prevent tags from being used,
  even by accident.
• Both the new reserved_tags and the old oneof attributes can now specify
  inclusive ranges of tag numbers instead of only single tags. For now, in
  oneof this is limited to 100 tags per range because more than that is just
  too many.
• bilrost-derive, which contains the derive macros, is now no_std. This
  doesn't really change what it's capable of at all but it does make it easier
  to prove it doesn't accidentally preclude using std.

Fixes

• Explicitly instantiate and invoke the const-time assertions that check the
  tags match between a Oneof type and its inclusion in a Message. Before this
  the asserts probably would never run.

Cleanups

• The "opaque" message types are now always available, and no longer require a
  dependency or a crate feature. The "opaque" feature will be removed in a
  future version.
• The "derived message tests" have been moved from a binary with required
  features to an integration test. The "derive" feature and the "bilrost-derive"
  crate dependency are now always enabled in tests to support this.