namespace System.Numerics
{
    public readonly struct BigInteger : IComparable, IComparable<BigInteger>, IEquatable<BigInteger>, IFormattable, IParsable<BigInteger>, ISpanFormattable, ISpanParsable<BigInteger>, IUtf8SpanFormattable, IUtf8SpanParsable<BigInteger>, IAdditionOperators<BigInteger, BigInteger, BigInteger>, IAdditiveIdentity<BigInteger, BigInteger>, IBinaryInteger<BigInteger>, IBinaryNumber<BigInteger>, IBitwiseOperators<BigInteger, BigInteger, BigInteger>, IComparisonOperators<BigInteger, BigInteger, bool>, IDecrementOperators<BigInteger>, IDivisionOperators<BigInteger, BigInteger, BigInteger>, IEqualityOperators<BigInteger, BigInteger, bool>, IIncrementOperators<BigInteger>, IModulusOperators<BigInteger, BigInteger, BigInteger>, IMultiplicativeIdentity<BigInteger, BigInteger>, IMultiplyOperators<BigInteger, BigInteger, BigInteger>, INumber<BigInteger>, INumberBase<BigInteger>, IShiftOperators<BigInteger, int, BigInteger>, ISignedNumber<BigInteger>, ISubtractionOperators<BigInteger, BigInteger, BigInteger>, IUnaryNegationOperators<BigInteger, BigInteger>, IUnaryPlusOperators<BigInteger, BigInteger>
    {
        public static BigInteger CopySign(BigInteger value, BigInteger sign);
    }
}