/** GWT emulated version of {@link ImmutableCollection.Builder}. */
  public abstract static class Builder<E> {
    static final int DEFAULT_INITIAL_CAPACITY = 4;

    Builder() {}

    static int expandedCapacity(int oldCapacity, int minCapacity) {
      if (minCapacity < 0) {
        throw new AssertionError("cannot store more than MAX_VALUE elements");
      }
      // careful of overflow!

    assertEquals(1, ImmutableCollection.Builder.expandedCapacity(0, 1));
    assertEquals(2, ImmutableCollection.Builder.expandedCapacity(0, 2));
    assertEquals(2, ImmutableCollection.Builder.expandedCapacity(1, 2));
    assertEquals(
        Integer.MAX_VALUE, ImmutableCollection.Builder.expandedCapacity(0, Integer.MAX_VALUE));
    assertEquals(
        Integer.MAX_VALUE, ImmutableCollection.Builder.expandedCapacity(1, Integer.MAX_VALUE));
    assertEquals(

    assertEquals(1, ImmutableCollection.Builder.expandedCapacity(0, 1));
    assertEquals(2, ImmutableCollection.Builder.expandedCapacity(0, 2));
    assertEquals(2, ImmutableCollection.Builder.expandedCapacity(1, 2));
    assertEquals(
        Integer.MAX_VALUE, ImmutableCollection.Builder.expandedCapacity(0, Integer.MAX_VALUE));
    assertEquals(
        Integer.MAX_VALUE, ImmutableCollection.Builder.expandedCapacity(1, Integer.MAX_VALUE));
    assertEquals(