[FEATURE] Use java.lang.LazyConstant for lazy getters

[xtay2]

Describe the feature
With LazyConstant (formerly StableValue), Java will receive a new default mechanism for lazy initialization which supports constant folding. This issue proposes to change the implementation of the @Getter(lazy = true) to use LazyConstants under the hood:

@Getter(lazy=true) private final double[] cached = expensive();
  
  private double[] expensive() {
    double[] result = new double[1000000];
    for (int i = 0; i < result.length; i++) {
      result[i] = Math.asin(i);
    }
    return result;
  }

will become:

@Getter(lazy=true) private final LazyConstant<double[]> cached = LazyConstant.of(() -> {
    double[] result = new double[1000000];
    for (int i = 0; i < result.length; i++) {
      result[i] = Math.asin(i);
    }
    return result;
  });
  
  private double[] expensive() {
    return expensive.get();
  }

Describe the target audience
Everyone could benefit from the performance boost unlocked through constant folding.

Additional context
This would introduce breaking (source) changes, because Lombok would have to change the datatype of the field. As the Lombok documentation already discourages direct field access, I'd argue, that this would be an excusable price to pay.

[xtay2]

The lombok replacement, as stated in the issue, is one of multiple possibilities, as for how a transformation could be applied. Currently, StableValues require the programmer to write a boilerplate getter (which is the main pain point). This could also look like:

@Getter 
private final LazyConstant<double[]> cached = LazyConstant.of(() -> {
    double[] result = new double[1000000];
    for (int i = 0; i < result.length; i++) {
      result[i] = Math.asin(i);
    }
    return result;
  });

and Lombok would just add:

private double[] expensive() {
   return expensive.get();
}

[nealeu]

From reading about LazyConstant, this could also be applied to the code generated by the logger annotations (i.e. @Slf4j etc), and this would provide startup benefits.
All LazyConstant features could be enabled selectively in lombok.config