Linq Median

public static TNumber Median<TNumber>(this IEnumerable<TNumber> source) where TNumber : struct, INumber<TNumber>
    => Median(new ReadOnlySpan<TNumber>(source.ToArray()));

public static TNumber Median<TNumber>(this TNumber[] source) where TNumber : struct, INumber<TNumber>
    => Median(new ReadOnlySpan<TNumber>(source));

public static TNumber Median<TNumber>(this ReadOnlySpan<TNumber> source) where TNumber : struct, INumber<TNumber>
{
    if (source.IsEmpty)
    {
        return TNumber.Zero;
    }

    if (source.Length == 1)
    {
        return source[0];
    }

    if (source.Length == 2)
    {
        checked
        {
            return (source[0] + source[1]) / TNumber.CreateChecked(2);
        }
    }

    var sourceCopy = new Span<TNumber>(source.ToArray());
    MemoryExtensions.Sort(sourceCopy);

    checked
    {
        if (sourceCopy.Length % 2 == 0)
        {
            return (sourceCopy[sourceCopy.Length / 2] + sourceCopy[(sourceCopy.Length / 2) - 1]) / TNumber.CreateChecked(2);
        }

        return sourceCopy[sourceCopy.Length / 2];
    }
}