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I read the code of Reactive Extension, then I find this code 

private readonly IObservable<TSource> _source;
protected override IDisposable Run(IObserver<TResult> observer, IDisposable cancel, Action<IDisposable> setSink)
{
    var sink = new _(this, observer, cancel);
    setSink(sink);
    return _source.SubscribeSafe(sink);
}

I find that the method SubscribeSafe(sink) is in the class ObservableExtensions, and the class isn't implement the interface IObservable. Why the parameter _source have the member function SubscribeSafe()?

Moti Azu
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Tyoshi
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1 Answers1

2

It's because the methods in ObservableExtensions are extension methods. You can read about them here.

Moti Azu
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