LazyDataProxy how to pass extra args to url

I’m trying to use Dynamic Loading. However not so many examples.
I still have 3 issues:

  1. How to pass extra paras to the server side, except for manually appending to url? The paras pass to LazyDataProxy config are not sent to server. There’re only two paras (from and limit) sent to the server.
  2. How to hook the response from the server, and pass the data to the front side data collection. The predefined structure {data:[], total_count:int, from:int} , but I define a new structure for all the server side controller, in case return some extra information. How can I get the response and reconstruct the acceptable {data,total_count, from} structure to the front data collection?
  3. Could you provide an example of server side code?

Thx