OCaml Log message printer

Question

My `lwt_reporter` is as follows. It compiles and seems to work barring one instance.

```
let lwt_reporter file =
  let buf_fmt ~like =
    let b = Buffer.create 512 in
    Fmt.with_buffer ~like b,
    fun () -> let m = Buffer.contents b in Buffer.reset b; m
  in
  let app, app_flush = buf_fmt ~like:Fmt.stdout in
  let dst, dst_flush = buf_fmt ~like:Fmt.stderr in
  let reporter = Logs_fmt.reporter ~app ~dst () in
  let report src level ~over k msgf =
    let k () =
       let write () =
         Lwt_io.open_file ~flags:[Unix.O_WRONLY; Unix.O_CREAT; Unix.O_APPEND]
           ~perm:0o777 ~mode:Lwt_io.Output file
        >>= fun fd -> (
          match level with
          | Logs.App -> Lwt_io.write fd (app_flush ())
          | _ -> Lwt_io.write fd (dst_flush ())
        )
          >>= fun () ->
            Lwt_io.close fd
    in
     let unblock () = over (); Lwt.return_unit in
      Lwt.finalize write unblock |> Lwt.ignore_result;
      k ()
    in
    reporter.Logs.report src level ~over:(fun () -> ()) k msgf;
  in
  { Logs.report = report }

let setup cmid =
  Logs.set_reporter (lwt_reporter  ("/Users/anu/Documents/rays/raft1/raft" ^ (Int.to_string cmid ) ^ ".log"));
  Logs.set_level (Some Info);
  Lwt.return_unit

```
My functions to print the messages are of the form


```
let pp_log6 out index term cmid  = Format.fprintf out "Votng procedure [Index=%d, Candidate ID =%d,
 term at last log=%d]" index cmid term

let pp_log1 out t  =
  Format.fprintf out " becomes Follower with term %ld " t

let log_message1 args pp =
  Logs_lwt.app @@ fun m ->
  args (fun k n  -> m ~tags:(stamp) " %a %a" pp  k pp n )(* No compilation error*)

let log_message2 args pp =
  Logs_lwt.app @@ fun m ->
  args (fun k n n1 n2 -> m ~tags:(stamp)
         "  %a " pp (  k  n  n1  n2 ))

```
While log_message1 has no problem, log_message2 throws an error.


```
 let _ = log_message2 (fun args -> args  term candidate_id index_at_last_log term_at_last_log) pp_log6 in
 .......
```                                                                                                       ^^^^^^^
Error: The value "pp_log6" has type
         "Containers.Stdlib.Format.formatter -> int -> int -> int -> unit"
       but an expression was expected of type
         "Containers.Stdlib.Format.formatter -> int -> unit"
       Type "int -> int -> unit" is not compatible with type "unit"

```
Moreover I am assuming the pp_log text messages are inside that function and are not passed from the call site through log_message type of functions. So I would need multiple combinations depending on the number of arguments)args). Is there a different way ?

I understand messages are created only when the logger levels are turned on and not before that.

OCaml Log message printer

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