This pull request introduces a mechanism to subscribe to asynchronous error notifications within the Switcher client, particularly useful for scenarios where throttle and silent mode are enabled. It also adds tests to verify that errors are properly captured and cleared when using silent mode.

Error Notification Subscription:

• Added a subscribe_notify_error static method to the Client and ExecutionLogger classes, allowing consumers to register a callback that will be invoked when an asynchronous error occurs. This is particularly useful for handling errors in silent or throttled modes. [1] [2]
• Implemented the _notify_error method in the Switcher class to trigger the registered error callback when exceptions are caught during remote criteria execution. [1] [2]

Testing Enhancements:

• Updated test_switcher_silent_mode.py to register an error notification callback, assert that errors are captured when remote API calls fail, and verify that errors are cleared after silent mode expires or the API is restored. [1] [2] [3] [4]