public static T Random <T>([NotNull] this IEnumerable <T> source)
{
// Buffer all elements
var asReadOnlyList = source as IReadOnlyList <T> ?? source.ToArray();
// If there are no elements - throw
if (!asReadOnlyList.Any())
{
throw new InvalidOperationException("Sequence contains no elements.");
}
return(asReadOnlyList[RandomEx.GetInt(0, asReadOnlyList.Count)]);
}