Make read buffer size configurable again

This refs #18 in that users can now set the buffer size they want. It
also gets rid of a pending `TODO` in the code.

async/httpaf_async.ml

@@ -90,16 +90,17 @@ let read fd buffer =
 open Httpaf
 
 module Server = struct
-  let create_connection_handler ?config ~request_handler ~error_handler =
+  module Config = Server_connection.Config
+
+  let create_connection_handler ?(config=Config.default) ~request_handler ~error_handler =
     fun client_addr socket ->
       let fd     = Socket.fd socket in
       let writev = Faraday_async.writev_of_fd fd in
       let request_handler = request_handler client_addr in
       let error_handler   = error_handler client_addr in
-      let conn = Server_connection.create ?config ~error_handler request_handler in
+      let conn = Server_connection.create ~config ~error_handler request_handler in
       let read_complete = Ivar.create () in
-      (* XXX(seliopou): Make this configurable *)
-      let buffer = Buffer.create 0x1000 in
+      let buffer = Buffer.create config.read_buffer_size in
       let rec reader_thread () =
         match Server_connection.next_read_operation conn with
         | `Read ->

lib/httpaf.mli

@@ -695,7 +695,8 @@ end
 module Server_connection : sig
   module Config : sig
     type t =
-      { response_buffer_size      : int (** Default is [1024] *)
+      { read_buffer_size          : int (** Default is [4096] *)
+      ; response_buffer_size      : int (** Default is [1024] *)
       ; response_body_buffer_size : int (** Default is [4096] *)
       }
 

lib/server_connection.ml

@@ -48,11 +48,13 @@ module Writer = Serialize.Writer
 
 module Config = struct
   type t =
-    { response_buffer_size      : int
+    { read_buffer_size          : int
+    ; response_buffer_size      : int
     ; response_body_buffer_size : int }
 
   let default =
-    { response_buffer_size      = 0x400
+    { read_buffer_size          = 0x1000
+    ; response_buffer_size      = 0x400
     ; response_body_buffer_size = 0x1000 }
 end
 
@@ -128,7 +130,7 @@ let create ?(config=Config.default) ?(error_handler=default_error_handler) reque
     { Config
     . response_buffer_size
     ; response_body_buffer_size
-    } = config
+    ; _ } = config
   in
   let writer = Writer.create ~buffer_size:response_buffer_size () in
   let request_queue = Queue.create () in

lwt/httpaf_lwt.ml

@@ -78,20 +78,19 @@ module Server = struct
   type request_handler =
     Lwt_unix.file_descr Httpaf.Server_connection.request_handler
 
+  module Config = Httpaf.Server_connection.Config
 
-
-  let create_connection_handler ?config ~request_handler ~error_handler =
+  let create_connection_handler ?(config=Config.default) ~request_handler ~error_handler =
     fun client_addr socket ->
       let module Server_connection = Httpaf.Server_connection in
       let connection =
         Server_connection.create
-          ?config
+          ~config
           ~error_handler:(error_handler client_addr)
           (request_handler client_addr)
       in
 
-
-      let read_buffer = Buffer.create 0x1000 in
+      let read_buffer = Buffer.create config.read_buffer_size in
       let read_loop_exited, notify_read_loop_exited = Lwt.wait () in
 
       let rec read_loop () =