rewrite ratelimiting and api route builder (#1667)

* rewrite ratelimiting and api route builder

* more stuff

* let people pass their own handlers

* Update burst.js

* Update RequestHandler.js

* Update burst.js

* Update sequential.js

* Update RequestHandler.js

src/client/rest/RequestHandlers/Burst.js

@@ -1,65 +0,0 @@
-const RequestHandler = require('./RequestHandler');
-const DiscordAPIError = require('../DiscordAPIError');
-
-class BurstRequestHandler extends RequestHandler {
-  constructor(restManager, endpoint) {
-    super(restManager, endpoint);
-
-    this.client = restManager.client;
-
-    this.limit = Infinity;
-    this.resetTime = null;
-    this.remaining = 1;
-    this.timeDifference = 0;
-
-    this.resetTimeout = null;
-  }
-
-  push(request) {
-    super.push(request);
-    this.handle();
-  }
-
-  execute(item) {
-    if (!item) return;
-    item.request.gen().end((err, res) => {
-      if (res && res.headers) {
-        this.limit = Number(res.headers['x-ratelimit-limit']);
-        this.resetTime = Number(res.headers['x-ratelimit-reset']) * 1000;
-        this.remaining = Number(res.headers['x-ratelimit-remaining']);
-        this.timeDifference = Date.now() - new Date(res.headers.date).getTime();
-      }
-      if (err) {
-        if (err.status === 429) {
-          this.queue.unshift(item);
-          if (res.headers['x-ratelimit-global']) this.globalLimit = true;
-          if (this.resetTimeout) return;
-          this.resetTimeout = this.client.setTimeout(() => {
-            this.remaining = this.limit;
-            this.globalLimit = false;
-            this.handle();
-            this.resetTimeout = null;
-          }, Number(res.headers['retry-after']) + this.client.options.restTimeOffset);
-        } else {
-          item.reject(err.status === 400 ? new DiscordAPIError(res.request.path, res.body) : err);
-          this.handle();
-        }
-      } else {
-        this.globalLimit = false;
-        const data = res && res.body ? res.body : {};
-        item.resolve(data);
-        this.handle();
-      }
-    });
-  }
-
-  handle() {
-    super.handle();
-    if (this.remaining <= 0 || this.queue.length === 0 || this.globalLimit) return;
-    this.execute(this.queue.shift());
-    this.remaining--;
-    this.handle();
-  }
-}
-
-module.exports = BurstRequestHandler;