Aio-pika

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***Release notes***

In this release, there are many changes to the internal API and bug fixes
related to sudden disconnection and correct recovery after reconnection.

Unfortunately, the behavior that was in version 7.x was slightly affected.
It's the reason the major version has been updated.

The entire set of existing tests passes with minimal changes, therefore,
except for some minor changes in behavior, the user code should
work either without any modifications or with minimal changes,
such as replacing removed deprecated functions with alternatives.

This release has been already tested in a working environment, and now it seems
that we have completely resolved all the known issues related to
recovery after network failures.

***Changes***:

* Added tests for unexpected network connection resets and fixed
many related problems.
* Added `UnderlayChannel` and `UnderlayConneciton`, this is `NamedTuple`s
contains all connection and channel related properties.
The `aiormq.Connection` and `aiormq.Channel` objects
are now packaged in this `NamedTuple`s and can be atomically assigned
to `aio_pika.Connection` and `aio_pika.Channel` objects.
The main benefit is the not needed to add locks during the connection,
in the best case, the container object is assigned to callee as usual,
however, if something goes wrong during the connection, there is no need to
clear something in `aio_pika.RobustConnection` or `aio_pika.RobustChannel`.
* An `__init__` method is now a part of abstract classes for most
`aio_pika` entities.
* Removed explicit relations between `aio_pika.Channel`
and `aio_pika.Connection`. Now you can't get a `aio_pika.Connection`
instance from the `aio_pika.Channel` instance.
* Fixed a bug that caused the whole connection was closed when a timeout
occurred in one of the channels, in case the channel was waiting for a
response frame to an amqp-rpc call.
* Removed deprecated `add_close_callback` and `remove_close_callback` methods
in `aio_pika.Channel`.
Use `aio_pika.Channel.close_callbacks.add(callback, ...)` and
`aio_pika.Channel.close_callbacks.remove(callback, ...)` instead.
* Fixed a bug in `aio_pika.RobustChannel` that caused `default_exchane`
broken after reconnecting.
* The `publisher_confirms` property of `aio_pika.Channel` is public now.
* Function `get_exchange_name` is public now.
* Fixed an error in which the queue iterator could enter a deadlock state, with
a sudden disconnection.
* The new entity `OneShotCallback` helps, for example, to call all the closing
callbacks at the channel if the `Connection` was unexpectedly closed, and
the channel closing frame did not come explicitly.

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* Make `aio_pika.patterns.rpc` more extendable.

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* Fixes in documentation

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This release brings support for a new version of `aiormq`, which is used as
a low-level driver for working with AMQP.

The release contains a huge number of changes in the internal structure of the
library, mainly related to type inheritance and abstract types, as well
as typehints checking via mypy.

The biggest change to the user API is the violation of the inheritance order,
due to the introduction of abstract types, so this release is a major one.

Changes

* There are a lot of changes in the structure of the library,
due to the widespread use of typing.
* `aio_pika.abc` module now contains all types and abstract class prototypes.
* Modern `aiormq~=6.1.1` used.
* Complete type checks coverage via mypy.
* The interface of `aio_pika`'s classes has undergone minimal changes,
but you should double-check your code before migrating, at least because
almost all types are now in `aio_pika.abc`. Module `aio_pika.types`
still exists, but will produce a `DeprecationWarning`.
* Default value for argument `weak` is changed to `False` in
`CallbackCollection.add(func, weak=False)`.


Known 6.x to 7.x migration issues

* `pamqp.specification` module didn't exist in `pamqp==3.0.1` so you have to
change it:
* `pamqp.commands` for AMPQ-RPC–relates classes
* `pamqp.base` for `Frame` class
* `pamqp.body` for `ContentBody` class
* `pamqp.commands` for `Basic`, `Channel`, `Confirm`, `Exchange`,
`Queue`, `Tx` classes.
* `pamqp.common` for `FieldArray`, `FieldTable`, `FieldValue` classes
* `pamqp.constants` for constants like `REPLY_SUCCESS`.
* `pamqp.header` for `ContentHeader` class.
* `pamqp.heartbeat` for `Heartbeat` class.
* Type definitions related to imports from `aio_pika` might throw warnings
like `'SomeType' is not declared in __all__ `. This is a normal situation,
since now it is necessary to import types from `aio_pika.abc`. In this
release, these are just warnings, but in the next major release, this will
stop working, so you should take care of changes in your code.

Just use `aio_pika.abc` in your imports.

The list of deprecated imports:
* `from aio_pika.message import ReturnCallback`
* `from aio_pika.patterns.rpc import RPCMessageType` - renamed to
`RPCMessageTypes`
* `import aio_pika.types` - module deprecated use `aio_pika.abc` instead
* `from aio_pika.connection import ConnectionType`

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* explicit `Channel.is_user_closed` property
* user-friendly exception when channel has been closed
* reopen channels which are closed from the broker side

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* Fix flapping test test_robust_duplicate_queue 424
* Fixed callback on_close for rpc 424