In the previous section, we discussed reactive programming and went through its model. In this section, we will discuss the Microsoft implementation of reactive programming. In response to reactive programming in .NET Core, we have various interfaces that provide a way to implement reactive programming in our application.

IObservable<T> is a generic interface that is defined in the System namespace and declared as public interface IObservable<out T>. Here, T represents a generic type of parameter that provides notification information. In simple terms, this interface helps us to define a provider for notifications, and these notifications can be pushed for information. You can use the observer pattern while implementing the IObservable<T> interface in your application.