using System;

using System.Threading.Tasks;

using System.Reactive.Subjects;

public class Program

{

    public static async Task Main()

    {

        Logger.Write("Start!");

        var source = new Subject<float>();

        var handler = new SubjectHandler<float>(source);

        handler.AsObservable().Subscribe(x => Logger.Write($"handler >>> {x}"));

        source.OnNext(3.4f);

        await Task.Delay(1200);

    }

}

​

public class SubjectHandler<T>

{

            private readonly Subject<T> _source;

        private readonly Subject<T> _subject = new Subject<T>();

​

        public SubjectHandler(Subject<T> source)

        {

            _source = source;

        }

​

        public IObservable<T> AsObservable()

        {

            _source.Subscribe(OnSourceValueChanged);

            return _subject;

        }

​

        private void OnSourceValueChanged(T value)

        {

            OnSourceValueChangedAsync(value).Forget();

        }

​

        private async Task OnSourceValueChangedAsync(T value)

        {

            await Task.Delay(1000);

            _subject.OnNext(value);

        }

}

​

public static class Logger

{

    public static void Write<T>(T obj)

    {

        Console.WriteLine($"{DateTime.Now} : {obj}");

    }

}

​

public static class TaskExtensions

{

    public static void Forget(this Task task)

    {

        task.ContinueWith(t =>

                          {

                              Logger.Write("Exception occured!!!");

                              Logger.Write(t.Exception);

                          }, TaskContinuationOptions.OnlyOnFaulted);

    }

}