return new Builder<>();
  }

  /**
   * A builder for creating immutable type-to-instance maps. Example:
   *
   * <pre>{@code
   * static final ImmutableTypeToInstanceMap<Handler<?>> HANDLERS =
   *     ImmutableTypeToInstanceMap.<Handler<?>>builder()
   *         .put(new TypeToken<Handler<Foo>>() {}, new FooHandler())
   *         .put(new TypeToken<Handler<Bar>>() {}, new SubBarHandler())
   *         .build();