How can you implement real-time updates in GraphQL using subscriptions?

The subscriptions feature in GraphQL enables clients to receive real-time data from the server over a persistent connection, usually through WebSockets, which is useful for implementing real-time updates. When a client subscribes to a specific event, the GraphQL server pushes updates to the client as the relevant data changes, keeping the client in sync. This is especially useful for features such as live chats, real-time notifications, or any scenario in which data must be updated in real time on the client side.