AsOutputKind(this IObservable <string> source, OutputOrErrorKind kind) =>
from line in source ?? throw new ArgumentNullException(nameof(source))
select new OutputOrErrorLine(kind, line);
Filter(this IObservable <OutputOrErrorLine> source, OutputOrErrorKind kind) =>
from line in source ?? throw new ArgumentNullException(nameof(source))
where line.Kind == kind
select line.Value;
public static void Deconstruct <TLine>(this TLine line,
out OutputOrErrorKind kind,
out string value)
where TLine : IOutputOrErrorLine =>
(kind, value) = line is null
? throw new ArgumentNullException(nameof(line))
