Optimizely-sdk

Bug Fixes:
* Fixed [installation issue](https://github.com/optimizely/python-sdk/issues/220) on Windows. ([#224](https://github.com/optimizely/python-sdk/pull/224))
* Fixed batch event processor deadline reset issue. ([227](https://github.com/optimizely/python-sdk/pull/227))
* Added more batch event processor debug messages. ([228](https://github.com/optimizely/python-sdk/pull/228))

New Features:
* Added support for event batching via the event processor.
* Events generated by methods like `activate`, `track`, and `is_feature_enabled` will be held in a queue until the configured batch size is reached, or the configured flush interval has elapsed. Then, they will be batched into a single payload and sent to the event dispatcher.
* To configure event batching, set the `batch_size` and `flush_interval` properties when initializing instance of [BatchEventProcessor](https://github.com/optimizely/python-sdk/blob/3.3.x/optimizely/event/event_processor.py#L45).
* Event batching is disabled by default. You can pass in instance of `BatchEventProcessor` when creating `Optimizely` instance to enable event batching.
* Users can subscribe to `LogEvent` notification to be notified of whenever a payload consisting of a batch of user events is handed off to the event dispatcher to send to Optimizely's backend.
* Introduced blocking timeout in `PollingConfigManager`. By default, calls to `get_config` will block for maximum of 10 seconds until config is available.

Bug Fixes:
* Fixed incorrect log message when numeric metric is not used. ([217](https://github.com/optimizely/python-sdk/pull/217))

New Features:

- Added support for automatic datafile management via [PollingConfigManager](https://github.com/optimizely/python-sdk/blob/3.2.x/optimizely/config_manager.py#L151):
- The [PollingConfigManager](https://github.com/optimizely/python-sdk/blob/3.2.x/optimizely/config_manager.py#L151) is an implementation of the [BaseConfigManager](https://github.com/optimizely/python-sdk/blob/3.2.x/optimizely/config_manager.py#L32).
- Users may provide one of datafile or SDK key (`sdk_key`) or both to `optimizely.Optimizely`. Based on that the SDK will use the [StaticConfigManager](https://github.com/optimizely/python-sdk/blob/3.2.x/optimizely/config_manager.py#L73) or the [PollingConfigManager](https://github.com/optimizely/python-sdk/blob/3.2.x/optimizely/config_manager.py#L151). Refer to the [README](https://github.com/optimizely/python-sdk/blob/3.2.x/README.rst) for more instructions.
- An initial datafile can be provided to the `PollingConfigManager` to bootstrap before making HTTP requests for the hosted datafile.
- Requests for the datafile are made in a separate thread and are scheduled with fixed delay.
- Configuration updates can be subscribed to by adding the Optimizely config notification.
- Introduced `Optimizely.get_feature_variable` API. ([191](https://github.com/optimizely/python-sdk/pull/191))

Deprecated:

- NotificationCenter.clear_notifications is deprecated as of this release. Please use `NotificationCenter.clear_notification_listeners`. ([182](https://github.com/optimizely/python-sdk/pull/182))
- `NotificationCenter.clear_all_notifications` is deprecated as of this release. Please use `NotificationCenter.clear_all_notification_listeners`. ([182](https://github.com/optimizely/python-sdk/pull/182))

New Features:

- Added support for automatic datafile management via [PollingConfigManager](https://github.com/optimizely/python-sdk/blob/3.2.x/optimizely/config_manager.py#L151):
- The [PollingConfigManager](https://github.com/optimizely/python-sdk/blob/3.2.x/optimizely/config_manager.py#L151) is an implementation of the [BaseConfigManager](https://github.com/optimizely/python-sdk/blob/3.2.x/optimizely/config_manager.py#L32).
- Users may provide one of datafile or SDK key (`sdk_key`) or both to `optimizely.Optimizely`. Based on that the SDK will use the [StaticConfigManager](https://github.com/optimizely/python-sdk/blob/3.2.x/optimizely/config_manager.py#L73) or the [PollingConfigManager](https://github.com/optimizely/python-sdk/blob/3.2.x/optimizely/config_manager.py#L151). Refer to the [README](https://github.com/optimizely/python-sdk/blob/3.2.x/README.rst) for more instructions.
- An initial datafile can be provided to the `PollingConfigManager` to bootstrap before making HTTP requests for the hosted datafile.
- Requests for the datafile are made in a separate thread and are scheduled with fixed delay.
- Configuration updates can be subscribed to by adding the Optimizely config notification.
- Introduced `Optimizely.get_feature_variable` API. ([191](https://github.com/optimizely/python-sdk/pull/191))

Deprecated:

- NotificationCenter.clear_notifications is deprecated as of this release. Please use `NotificationCenter.clear_notification_listeners`. ([182](https://github.com/optimizely/python-sdk/pull/182))
- `NotificationCenter.clear_all_notifications` is deprecated as of this release. Please use `NotificationCenter.clear_all_notification_listeners`. ([182](https://github.com/optimizely/python-sdk/pull/182))

New Features:

- Introduced Decision notification listener to be able to record:
- Variation assignments for users activated in an experiment.
- Feature access for users.
- Feature variable value for users.

Bug Fixes:

- Feature variable APIs now return default variable value when
featureEnabled property is false.
([\171](https://github.com/optimizely/python-sdk/pull/171))

Deprecated:

- Activate notification listener is deprecated as of this release.
Recommendation is to use the new Decision notification listener.
Activate notification listener will be removed in the next major
release.