All Known Implementing Classes:

GuavaLibrary, JavaxPackage, Jsr305, SourceLevel
```
public interface Feature<T extends Feature<T>>
```
A feature encapsulates the availability of a type or source level feature that can be used in the source written to a SourceBuilder, such as Java language-level features, or Guava types and methods.
A feature will typically provide a FeatureType constant that can be passed to SourceBuilder#feature(FeatureType) to determine the current status of a feature. For instance, to determine whether java.util.Objects is available for use:
```
code.feature(SOURCE_LEVEL).javaUtilObjects().isPresent()
```

Interface Feature<T extends Feature<T>>