How to check if the user is listening on gRPC async stream from server

Question

I have a server which is supposed to stream a set of endless data to the web client when client subscribes to it using grpc-web but my problem is that the server continues sending data even after user goes to some other page and leaves the streaming area I'm looking for a way which server could be able to control if the user is listening on stream or not and by that i would be able cancel streaming on the server note that I'm using grpc-web streaming and proto3 server is on python and client is angular and typescript server stubs were created with betterproto plugin any help or idea to handle this problem will be appreciated