Currently it is impossible to tie specific behavior when a client requests a part from the server for streaming purposes. For example, I want to pass along additional information about an part when a client stream it in. However, there is currently no way on the server to tell when this information is requested, so we cannot pass along additional information.
It would be nice if there was an even on the server like StreamingService.RequestedByClient:Connect(function(player, instance) end) that allows custom server behavior in response to a client streaming in new data.