0.27.1

Fixed

• A stream closed or dropped while the client is disconnected releases its
  channel. Its UNSUBSCRIBE reached the network task between two reconnection
  attempts and, being non-retryable, was failed with DisconnectedByPeer
  without the subscription being forgotten. The reconnection then subscribed the
  server again to the channel, for a subscriber that no longer existed, and
  every later subscribe to it on the same Client was refused with
  AlreadySubscribed until a message happened to arrive on it. A channel that
  stays quiet, like a per-user channel while its user is offline, stayed blocked
  for the life of the Client. Such an UNSUBSCRIBE now succeeds without being
  sent: a fresh connection is subscribed to nothing, so it has nothing left to
  do. PubSubStream::close therefore returns Ok during an outage.
• A subscription whose stream is gone no longer refuses a new subscriber. A
  subscribe to a channel whose previous stream had been dropped was refused
  with AlreadySubscribed until the server confirmed the UNSUBSCRIBE of that
  stream, so a caller that subscribed again right after a drop had to retry. It
  now takes the channel over at once.
• The crate builds again with warnings denied on Rust 1.99. That toolchain
  deprecates AtomicUsize::fetch_update in favour of try_update, which the
  1.88 MSRV does not have, so the test-only fault-injection countdown now
  decrements through a compare_exchange_weak loop that both accept. Its clippy
  also reports #[must_use] on BlockingCommands::monitor as redundant -- an
  async fn returns a future, already must_use -- so the attribute is gone,
  with no change to what a caller is warned about.