How to catch the metrics that are generated by Plug.Telemetry?

Questions / Help
1

Hi family I am working with Plug.Telemetry and trying to catch the metrics that are generated by it
this is my example:

defmodule PlugExample.Router do
  use Plug.Router
  plug Plug.Telemetry, event_prefix: [:http, :request] # metrics to generate
  plug :match
  plug Plug.Parsers, parsers: [:urlencoded, :multipart]
  plug :dispatch
  
  get "/" do
    Process.sleep(1000)
    send_resp(conn, 200, "Welcome")
  end
end

the metrics that are generated are captured and exposed by telemetry_metrics_prometheus :

counter("http.request.start", event_name: [:http, :request, :start], measurement: :value),
counter("http.request.stop", event_name: [:http, :request, :stop], measurement: :value),

and show in the following path http://localhost:8081/metrics

# HELP http_request_stop 
# TYPE http_request_stop counter
http_request_stop 1
# HELP http_request_start 
# TYPE http_request_start counter
http_request_start 1

however I do not know how to capture other metrics for example last_value as is shown :

last_value(“http.request.stop”, event_name: [:http, :request, :stop], measurement: :duration)

I mean if I want to capture with the last_value all metadata that is generated by Plug.Telemetry, I cannot.

for example, I want to capture something like this:

http_response_stop_duration{event_type="RESPONSE",message_id="123",method="POST",path="/pockets/retrieve",request_ending_time="2023-03-09 16:53:13.482000Z",status="SUCCESS",status_desc="200",systemId="123"} 55.0