private static ImmutableSet<String> parameterNames(ExecutableElement executableElement) {
    return executableElement.getParameters().stream()
        .map(v -> v.getSimpleName().toString())
        .collect(toImmutableSet());
  }
Use Kotlin reflection to build {@link Executable} instances for the constructors in {@code
ofClass} that include information about which parameters have default values.

@param metadata the {@code @kotlin.Metadata} annotation on {@code ofClass}
@param ofClass the class whose constructors should be returned
value/src/main/java/com/google/auto/value/processor/KotlinMetadata.java