Merge pull request #501 from Kraigie/ratelimiter-2.0

Convert ratelimiter into an async state machine

guides/intro/api.md

@@ -55,7 +55,7 @@ they're given or using `Nostrum.Api.request/4` to call an endpoint.
 
 To ensure that every request is handled properly, no matter if they're called
 asynchronously or not, nostrum funnels all requests through the
-`Nostrum.Api.Ratelimiter` GenServer.
+`Nostrum.Api.Ratelimiter` state machine.
 
 
 ## REST-only

guides/intro/intro.md

@@ -107,8 +107,8 @@ The following options are only used for testing nostrum itself.
 ## Logging
 
 nostrum uses Elixir's standard logger to inform you about regular and irregular
-events. Normal messages include Discord-requested shard reconnections,
-ratelimiter waits, and the `IDENTIFY` and `READY` events.
+events. Normal messages include Discord-requested shard reconnections and the
+`IDENTIFY` and `READY` events.
 
 The following metadata fields through logger:
 

lib/nostrum/api/base.ex

@@ -9,8 +9,7 @@ defmodule Nostrum.Api.Base do
   @type methods :: :get | :post | :put | :delete
 
   @spec request(pid, methods(), String.t(), iodata(), [{String.t(), String.t()}], Enum.t()) ::
-          {:error, :timeout | {:connection_error, any} | {:down, any} | {:stream_error, any}}
-          | {:ok, {non_neg_integer, [{String.t(), String.t()}], binary}}
+          :gun.stream_ref()
   def request(conn, method, route, body, raw_headers, params) do
     headers = process_request_headers(raw_headers)
     # Convert method from atom to string for `:gun`
@@ -23,23 +22,7 @@ defmodule Nostrum.Api.Base do
 
     full_route = "#{base_route()}#{route}?#{query_string}"
     headers = process_request_headers(headers, body)
-    stream = :gun.request(conn, method, full_route, headers, process_request_body(body))
-
-    case :gun.await(conn, stream) do
-      {:response, :fin, status, headers} ->
-        {:ok, {status, headers, ""}}
-
-      {:response, :nofin, status, headers} ->
-        {:ok, body} = :gun.await_body(conn, stream)
-        {:ok, {status, headers, body}}
-
-      {:error, :timeout} = result ->
-        Logger.debug("Request for #{inspect(full_route)} timed out")
-        result
-
-      {:error, _reason} = result ->
-        result
-    end
+    :gun.request(conn, method, full_route, headers, process_request_body(body))
   end
 
   def process_request_headers(headers, ""), do: :proplists.delete("content-type", headers)