ClientStreamInterceptor.go

type wrappedStream struct { 
	grpc.ClientStream
}

func newWrappedStream(s grpc.ClientStream) grpc.ClientStream {
	return &wrappedStream{s}
}

func (w *wrappedStream) RecvMsg(m interface{}) error {
  .....
	return w.ClientStream.RecvMsg(m)
}


func (w *wrappedStream) SendMsg(m interface{}) error {
	.....
	return w.ClientStream.SendMsg(m)
}

func exampleClientStreamInterceptor(ctx context.Context, desc *grpc.StreamDesc,
	cc *grpc.ClientConn, method string,	streamer grpc.Streamer, opts ...grpc.CallOption)
        (grpc.ClientStream, error) {
	 
  /*
     some logic before client stream
  */        
	s, err := streamer(ctx, desc, cc, method, opts...) 

	return newWrappedStream(s), nil 
}

func main() {
...  
	// Setting up a gRPC connection
	conn, err := grpc.Dial(address, grpc.WithInsecure(),grpc.WithStreamInterceptor(exampleClientStreamInterceptor)) 
...
}