Fixes #23757.

Before this commit, even if `reject` was called in the `subscribe`
method for an Action Cable channel, all actions on that channel could
still be invoked. This calls a `return` if a rejected connection tries
to invoke any actions on the channel.

Style/SpaceBeforeBlockBraces
Style/SpaceInsideBlockBraces
Style/SpaceInsideHashLiteralBraces

Fix all violations in the repository.

The current code base is not uniform. After some discussion,
we have chosen to go with double quotes by default.

Require our dependency and forgo the core ext version.

[Javan Makhmali, Jon Moss]

This addition of this notification hook will give users better visibility
into the messages being sent over the PubSub adapter.

* Use separate stream handler builders for easy override and testing.
* Fix worker pool execution that was silently failing since it only
  expected connection receivers.

Sparked by code in #24162.

* Rewrite docs
* Support blocks in addition to method names and Proc args
* Check for valid arguments
* Convert `periodically :method_name` to Proc callbacks
* Drop periodic runner methods from the worker pool
* Ensure we clear active periodic timers after shutdown

- Fixed ActionCable::Connection::ClientSocketTest that was overriding ActionCable::Connection::StreamTest test name
- Only add attr_readers for required attributes

Alternate implementation of #24162 with tests. The code had diverged
too far on master to pull that implemenation directly.

Fixes #23778
Close #24162

[Mattew Draper & Sean Griffin]

* Introduce a connection coder responsible for encoding Cable messages
  as WebSocket messages, defaulting to `ActiveSupport::JSON` and duck-
  typing to any object responding to `#encode` and `#decode`.
* Consolidate encoding responsibility to the connection. No longer
  explicitly JSON-encode from channels or other sources. Pass Cable
  messages as Hashes to `#transmit` and rely on it to encode.
* Introduce stream encoders responsible for decoding pubsub messages.
  Preserve the currently raw encoding, but make it easy to use JSON.
  Same duck type as the connection encoder.
* Revert recent data normalization/quoting (#23649) which treated
  `identifier` and `data` values as nested JSON objects rather than as
  opaque JSON-encoded strings. That dealt us an awkward hand where we'd
  decode JSON strings… or not, but always encode as JSON. Embedding
  JSON object values directly is preferably, no extra JSON encoding,
  but that should be a purposeful protocol version change rather than
  ambiguously, inadvertently supporting multiple message formats.

To move Action Cable logging to a LoggingSubscriber we need to pass the
log tags in the notification payload since Action Cable logging use the
Channel instance to tag the logs.

`skip` raises an exception to abort the execution of the test, so
`super` would never be called and thus `@rx_adapter` and `@tx_adapter`
would never have been defined at the time of teardown.

Define them just before skipping and zap the warnings.

EM::Hiredis were spewing screenfuls of warnings when running the Action Cable tests.

Copied over the technique that shushes up faye-websocket in the client tests, so
we can reduce the noise ratio.

Note: there's still warnings spewed after tests have finished when EM::Hiredis shuts
down. I haven't been able to shush them up yet.

We'll get `Errno::ECONNRESET` if the client forcibly disconnected.
Just close the socket rather than raising the exception.

Handle other errors in `ClientSocket#write`, too, mirroring the Faye
error handling which swallows all `StandardError` on write.

This commit adds ActiveSupport::Notifications instrumentation hooks
and a LogSuscriber to ActionCable::Channel::Base.

Fixes #22675

Allow channel identifiers and also data with no backslahes/escaping to be accepted by
the subscription storer.

This change makes ping into a message type, which
makes the whole protocol a lot more consistent.

Also fixes hacks on the client side to make this all
work.

Fixes #23471

Similar to the channel streaming side, these values must be strings for
ActionCable to behave as expected. The conversion will allow users to
send string-convertible values and get the expected behavior.

ActionCable does some things behind the scenes that expects these
"broadcasting"s or "channel"s to be strings. However it's not
immediately obvious that the value must be a string. So adding this
conversion ensures things work as expected.