:recycle: allow easier sub-classing of inferences

[ianardee]

Description

Allow users to more easily subclass by making inference properties protected.

Types of changes

• [x] Docs change / refactoring / dependency upgrade
• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] Requires a change to the official Guide documentation.