• closes Extract state persistence into a mixin-style base class #809, but I chose to make it a regular class and not a mixin (the initial attempt was super cumbersome and clashed with existing public interface of Statistics and SessionPool).
• will help with Properly implement RequestList #99

Key Changes

• Introduced a new RecoverableState helper class that:

  • Uses Pydantic models for state representation and validation
  • Handles state persistence to a KeyValueStore
  • Automatically registers/deregisters with event system for state persistence

• Refactored existing components to use the new abstraction:

  • Converted SessionPool to use RecoverableState for state management
  • Converted Statistics to use RecoverableState for state management
  • Converted KeyValueStore to use RecoverableState for autosaved values

Benefits

• More consistent handling of state persistence across the library
• Reduced code duplication for state management logic
• Better separation of concerns between state data and persistence logic