refactor(rest): switch api to fetch-like and provide strategies (#9416)

BREAKING CHANGE: NodeJS v18+ is required when using node due to the use of global `fetch`
BREAKING CHANGE: The raw method of REST now returns a web compatible `Respone` object.
BREAKING CHANGE: The `parseResponse` utility method has been updated to operate on a web compatible `Response` object.
BREAKING CHANGE: Many underlying internals have changed, some of which were exported.
BREAKING CHANGE: `DefaultRestOptions` used to contain a default `agent`, which is now set to `null` instead.

packages/rest/src/lib/utils/constants.ts

@@ -1,8 +1,12 @@
 import process from 'node:process';
+import { lazy } from '@discordjs/util';
 import { APIVersion } from 'discord-api-types/v10';
-import { Agent } from 'undici';
 import type { RESTOptions } from '../REST.js';
 
+const getUndiciRequest = lazy(async () => {
+	return import('../../strategies/undiciRequest.js');
+});
+
 export const DefaultUserAgent =
 	`DiscordBot (https://discord.js.org, [VI]{{inject}}[/VI])` as `DiscordBot (https://discord.js.org, ${string})`;
 
@@ -12,13 +16,7 @@ export const DefaultUserAgent =
 export const DefaultUserAgentAppendix = process.release?.name === 'node' ? `Node.js/${process.version}` : '';
 
 export const DefaultRestOptions = {
-	get agent() {
-		return new Agent({
-			connect: {
-				timeout: 30_000,
-			},
-		});
-	},
+	agent: null,
 	api: 'https://discord.com/api',
 	authPrefix: 'Bot',
 	cdn: 'https://cdn.discordapp.com',
@@ -34,6 +32,10 @@ export const DefaultRestOptions = {
 	hashSweepInterval: 14_400_000, // 4 Hours
 	hashLifetime: 86_400_000, // 24 Hours
 	handlerSweepInterval: 3_600_000, // 1 Hour
+	async makeRequest(...args) {
+		const strategy = await getUndiciRequest();
+		return strategy.makeRequest(...args);
+	},
 } as const satisfies Required<RESTOptions>;
 
 /**