ChangeLog generics for autorest v5

tools/azure-sdk-tools/changelog_generics.md

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+# Autorest v2 to v3
+
+
+## General Breaking changes
+
+This version uses a next-generation code generator that *might* introduce breaking changes.
+
+- Model signatures now use only keyword-argument syntax. All positional arguments must be re-written as keyword-arguments.
+  To keep auto-completion in most cases, models are now generated for Python 2 and Python 3. Python 3 uses the "*" syntax for keyword-only arguments.
+- Enum types now use the "str" mixin (class AzureEnum(str, Enum)) to improve the behavior when unrecognized enum values are encountered.
+  While this is not a breaking change, the distinctions are important, and are documented here:
+  https://docs.python.org/3/library/enum.html#others
+  At a glance:
+
+  - "is" should not be used at all.
+  - "format" will return the string value, where "%s" string formatting will return `NameOfEnum.stringvalue`. Format syntax should be prefered.
+
+- New Long Running Operation:
+
+  - Return type changes from `msrestazure.azure_operation.AzureOperationPoller` to `msrest.polling.LROPoller`. External API is the same.
+  - Return type is now **always** a `msrest.polling.LROPoller`, regardless of the optional parameters used.
+  - The behavior has changed when using `raw=True`. Instead of returning the initial call result as `ClientRawResponse`,
+    without polling, now this returns an LROPoller. After polling, the final resource will be returned as a `ClientRawResponse`.
+  - New `polling` parameter. The default behavior is `Polling=True` which will poll using ARM algorithm. When `Polling=False`,
+    the response of the initial call will be returned without polling.
+  - `polling` parameter accepts instances of subclasses of `msrest.polling.PollingMethod`.
+  - `add_done_callback` will no longer raise if called after polling is finished, but will instead execute the callback right away.
+
+# Autorest v3 to v4, if the package is single API
+
+
+## General Breaking changes
+
+This version uses a next-generation code generator that *might* introduce breaking changes if from some import.
+In summary, some modules were incorrectly visible/importable and have been renamed. This fixed several issues caused by usage of classes that were not supposed to be used in the first place.
+
+- HanaManagementClient cannot be imported from `azure.mgmt.hanaonazure.hana_management_client` anymore (import from `azure.mgmt.hanaonazure` works like before)
+- HanaManagementClientConfiguration import has been moved from `azure.mgmt.hanaonazure.hana_management_client` to `azure.mgmt.hanaonazure`
+- A model `MyClass` from a "models" sub-module cannot be imported anymore using `azure.mgmt.hanaonazure.models.my_class` (import from `azure.mgmt.hanaonazure.models` works like before)
+- An operation class `MyClassOperations` from an `operations` sub-module cannot be imported anymore using `azure.mgmt.hanaonazure.operations.my_class_operations` (import from `azure.mgmt.hanaonazure.operations` works like before)
+
+Last but not least, HTTP connection pooling is now enabled by default. You should always use a client as a context manager, or call close(), or use no more than one client per process.
+
+# Autorest v3 to v4, if the package is multiapi
+
+
+## General Breaking changes
+
+This version uses a next-generation code generator that *might* introduce breaking changes if you were importing from the v20xx_yy_zz API folders.
+In summary, some modules were incorrectly visible/importable and have been renamed. This fixed several issues caused by usage of classes that were not supposed to be used in the first place.
+
+- NetworkManagementClient cannot be imported from `azure.mgmt.network.v20xx_yy_zz.network_management_client` anymore (import from `azure.mgmt.network.v20xx_yy_zz` works like before)
+- NetworkManagementClientConfiguration import has been moved from `azure.mgmt.network.v20xx_yy_zz.network_management_client` to `azure.mgmt.network.v20xx_yy_zz`
+- A model `MyClass` from a "models" sub-module cannot be imported anymore using `azure.mgmt.network.v20xx_yy_zz.models.my_class` (import from `azure.mgmt.network.v20xx_yy_zz.models` works like before)
+- An operation class `MyClassOperations` from an `operations` sub-module cannot be imported anymore using `azure.mgmt.network.v20xx_yy_zz.operations.my_class_operations` (import from `azure.mgmt.network.v20xx_yy_zz.operations` works like before)
+
+Last but not least, HTTP connection pooling is now enabled by default. You should always use a client as a context manager, or call close(), or use no more than one client per process.
+
+# Autorest v4 to v5
+
+This version uses a next-generation code generator that introduces important breaking changes, but also important new features (like unififed authentication and async programming).
+
+## General breaking changes
+
+- Credential system has been completly revamped:
+
+  - `azure.common.credentials` or `msrestazure.azure_active_directory` instances are no longer supported, use the `azure-identity` classes instead: https://pypi.org/project/azure-identity/
+  - `credentials` parameter has been renamed `credential`
+
+- The `config` attribute no longer exists on a client, configuration should be passed as kwarg. Example: `MyClient(credential, subscription_id, enable_logging=True)`. For a complete set of
+  supported options, see the [parameters accept in init documentation of azure-core](https://github.com/Azure/azure-sdk-for-python/blob/master/sdk/core/azure-core/CLIENT_LIBRARY_DEVELOPER.md#available-policies)
+- You can't import a `version` module anymore, use `__version__` instead
+- Operations that used to return a `msrest.polling.LROPoller` now returns a `azure.core.polling.LROPoller` and are prefixed with `begin_`.
+- Exceptions tree have been simplified and most exceptions are now `azure.core.exceptions.HttpResponseError` (`CloudError` has been removed).
+- Most of the operation kwarg have changed. Some of the most noticeable:
+
+  - `raw` has been removed. Equivalent feature can be found using `cls`, a callback that will give access to internal HTTP response for advanced user
+  - For a complete set of
+  supported options, see the [parameters accept in Request documentation of azure-core](https://github.com/Azure/azure-sdk-for-python/blob/master/sdk/core/azure-core/CLIENT_LIBRARY_DEVELOPER.md#available-policies)
+
+## General new features
+
+- Type annotations support using `typing`. SDKs are mypy ready.
+- This client has now stable and official support for async. Check the `aio` namespace of your package to find the async client.
+- This client now support natively tracing library like OpenCensus or OpenTelemetry. See this [tracing quickstart](https://github.com/Azure/azure-sdk-for-python/tree/master/sdk/core/azure-core-tracing-opentelemetry) for an overview.