/// <summary>
/// Returns a data-producer that will yield
/// elements a sequence as long as a condition
/// is satsified; when the condition fails for an element,
/// that element and all subsequent elements are ignored.
/// </summary>
/// <param name="source">The source data-producer</param>
/// <param name="predicate">The condition to yield elements</param>
public static IDataProducer <TSource> TakeWhile <TSource>(this IDataProducer <TSource> source, DotNet20.Func <TSource, bool> predicate)
{
predicate.ThrowIfNull("predicate");
return(source.TakeWhile((x, index) => predicate(x)));
}