adjust documentation

README.md

@@ -52,7 +52,8 @@ open Lwt.Infix
 
 module Make (HTTP_client : Http_mirage_client.S) = struct
   let start http_client =
-    Http_mirage_client.one_request http_client "https://mirage.io/"
+    let body_f _response acc data = Lwt.return (acc ^ data) in
+    Http_mirage_client.one_request http_client "https://mirage.io/" body_f ""
     >>= function
     | Ok (resp, body) -> ...
     | Error _ -> ...

src/http_mirage_client.mli

@@ -36,3 +36,8 @@ val request :
   -> (response -> 'a -> string -> 'a Lwt.t)
   -> 'a
   -> (response * 'a, [> Mimic.error ]) result Lwt.t
+(** [request ~config ~tls_config t ~authenticator ~meth ~headers ~body
+     ~max_redirect ~follow_redirect url body_f body_init] does a HTTP request
+    to [url] using [meth] and the HTTP protocol in [config]. The response is
+    the value of this function. The body is provided in chunks (see [body_f]).
+    Reasonably defaults are used if not provided. *)