public static ISequence <TResult> CreateSingleResultOperator <TSource, TResult>(
ISequence <TSource> source,
Func <IIterator <TSource>, CancellationToken, Task <TResult> > evaluate
)
{
return(Create(context => Iterator.CreateSingleResultOperator <TSource, TResult>(source.Start(context), evaluate)));
}
public static ISequence <T> FirstOrDefault <T>(this ISequence <T> source)
{
return(Sequence.Create(context => Iterator.CreateSingleResultOperator <T, T>(source.Start(context), async(iter, cancel) =>
await iter.MoveNext(cancel).ConfigureAwait(false) ? iter.Current : default(T)
)));
}
