v10.4.0

• PkiEnvironment now supports adding multiple trust anchors. Previously, addTrustAnchor replaced any existing trust
  anchor. Get all added trust anchor certificates via getTrustAnchors. Remove a trust anchor via removeTrustAnchor
  by providing the Subject Public Key Info (SPKI) fingerprint.

• Fixes a bug which caused MLS messages that arrived out of order to be discarded instead of buffered for replay.

  When a message for epoch n + 1 arrived while the conversation was still in epoch n, CoreCrypto buffered it in the
  database, but a stale foreign key constraint rejected that write for every conversation which had already been
  established. The message was never replayed once the epoch advanced, producing a keystore error based on Sqlite
  ConstraintViolation, 787 instead.

  This bug affected versions 10.0.0-10.3.0; earlier versions had foreign key constraint checks disabled.

• Wiping a conversation, or abandoning an external join which the delivery service rejected, now also discards the
  messages and commits that conversation had buffered. Previously those rows stayed in the database indefinitely, with
  nothing able to read or remove them. This does not remove existing stale rows, but prevents new ones from leaking into
  the database.

• Operations within a CoreCrypto transaction are now applied to the database in the order they were performed, and all
  reads within a transaction reflect earlier writes in that same order. Previously reads would sometimes but not always
  reflect writes within the transaction, and operations would be played back into the database in arbitrary order
  (hashmap).

• proteusNewPrekeyAuto still reuses the ids of deleted prekeys before allocating new ones, but no longer ensures that
  those ids are reused in strictly ascending order.