* <ol>
 * <li>success - in which case only the model field is set
 * <li>success with warnings - model field + non-error model problems
 * <li>error - no model, but diagnostics
 * <li>error - (partial) model and diagnostics
 * </ol>
 * Could encode these variants as subclasses, but kept in one for now
 *
 * @param <T> the model type
 */
public class Result<T> {

    /**
     * Success without warnings

          <artifactId>apache-rat-plugin</artifactId>
          <configuration>
            <excludes combine.children="append">
              <exclude>src/assembly/maven/bin/m2.conf</exclude>
              <!-- these are partial scripts, resulting in mvn scripts -->
              <exclude>src/assembly/shared/init</exclude>
              <exclude>src/assembly/shared/init.cmd</exclude>
              <exclude>src/assembly/shared/mvnlauncher</exclude>

 * repository system instance(s) use {@link RepositorySystem#shutdown()} method on supplied instance(s).
 * <p>
 * Since Resolver 2.0 this class offers access to various components via public getters, and allows even partial object
 * graph construction.
 * <p>
 * Extend this class {@code createXXX()} methods and override to customize, if needed. The contract of this class makes