Version 9 - Epic

[fiseni]

This issue will act as an Epic and lists all planned changes for version 9. I'll keep updating the list as we work toward the new version.

Version 9 will focus on performance improvement, specifically reducing allocations and the memory footprint of using specifications. We'll try to avoid breaking changes for the public API surface, but the internals will be refactored. Folks who have been relying on the internals or have custom extensions might be affected by these changes.

• Update Specification constructors as public. #413
• Remove IEntity #414
• Reduce the Specification size. Set the initial state to null. #415
• Refactor Take/Skip state to non-nullable int. Define the default value to -1. #416
• Remove the Evaluator and Validator state from Specifications. #417
• Remove the state for the Query builder. Update it as a calculated property. #418
• Improve the specification builders. Select/SelectMany should be applied in the end. #419
• Add IsChainDiscarded thread-static field. #420
• Improve the C# implementation of the Like operator. #421
• Improve the Search in-memory evaluator. Implement a custom iterator and reduce allocations. #422
• Improve the Search EF evaluator. Reduce allocations. #423
• Refactor Search validator to allocation-free implementation. #424
• Refactor Include evaluator. Implement caching. #425
• Update expression constructs. Reduce size. #426