return BigIntegerToDoubleRounder.INSTANCE.roundToDouble(x, mode);
  }

  @GwtIncompatible
  private static class BigIntegerToDoubleRounder extends ToDoubleRounder<BigInteger> {
    static final BigIntegerToDoubleRounder INSTANCE = new BigIntegerToDoubleRounder();

    private BigIntegerToDoubleRounder() {}

    @Override