Method iterable

guava/src/com/google/common/base/Joiner.java:532–553

(
      @Nullable Object first, @Nullable Object second, @Nullable Object[] rest)

  }

  private static Iterable<@Nullable Object> iterable(
      @Nullable Object first, @Nullable Object second, @Nullable Object[] rest) {
    checkNotNull(rest);
    return new AbstractList<@Nullable Object>() {
      @Override
      public int size() {
        return rest.length + 2;
      }

      @Override
      public @Nullable Object get(int index) {
        switch (index) {
          case 0:
            return first;
          case 1:
            return second;
          default:
            return rest[index - 2];
        }
      }
    };
  }

  // cloned from ImmutableCollection
  private static int expandedCapacity(int oldCapacity, int minCapacity) {