public static TSource First <TSource>(this IReadOnlyList <TSource> source) { switch (source) { case TSource[] array: return(ArrayExtensions.First <TSource>(array)); default: return(ReadOnlyList.First <IReadOnlyList <TSource>, IEnumerator <TSource>, TSource>(source)); } }
public static TSource First <TSource>(this IEnumerable <TSource> source, Func <TSource, bool> predicate) { switch (source) { case TSource[] array: return(ArrayExtensions.First <TSource>(array, predicate)); default: return(FirstDowncasted <IEnumerable <TSource>, TSource> .First(source)); } }