@GwtIncompatible // NavigableMap
@ElementTypesAreNonnullByDefault
public final class TreeRangeMap<K extends Comparable, V> implements RangeMap<K, V> {

  private final NavigableMap<Cut<K>, RangeMapEntry<K, V>> entriesByLowerBound;

  public static <K extends Comparable, V> TreeRangeMap<K, V> create() {
    return new TreeRangeMap<>();
  }

  private TreeRangeMap() {
    this.entriesByLowerBound = Maps.newTreeMap();
  }

          putModel(model, range1, 1);
          putModel(model, range2, 2);
          putModel(model, range3, 3);
          RangeMap<Integer, Integer> test = TreeRangeMap.create();
          RangeMap<Integer, Integer> test2 = TreeRangeMap.create();
          // put range2 and range3 into test2, and then put test2 into test
          test.put(range1, 1);
          test2.put(range2, 2);
          test2.put(range3, 3);

          putModel(model, range1, 1);
          putModel(model, range2, 2);
          putModel(model, range3, 3);
          RangeMap<Integer, Integer> test = TreeRangeMap.create();
          RangeMap<Integer, Integer> test2 = TreeRangeMap.create();
          // put range2 and range3 into test2, and then put test2 into test
          test.put(range1, 1);
          test2.put(range2, 2);
          test2.put(range3, 3);