src: sharding cleanup and checkReady rewrite (#3393)

* src: Step 1 of who knows how many

* src: Remove accidentally committed test file

* src: Remove useless added property in package.json

* docs: Trailing spaces, come back >.>

* src: Buhbye uws, we will miss you..not!

* src: Move 'auto' shard selection from totalShardCount to shards

* src: tweak

* src: Filter out floats from shard IDs
You want half of a shard or what?

* src: Misc cleanup and bugfix for GUILD_BAN_ADD

* src: Rewrite checkReady

* src: Misse this while merging master into my branch

* typings: Bring these up to date

* typings: Forgot allReady event

* src: Don't checkReady if the shard isn't waiting for guilds

* src: Fix a possible bug for when the ws dies and the session becomes -1

* src: Hopefully fix last edge case that could case a shard to infinitely boot loop

* src: Rename totalShardCount to shardCount

* src: Small bugfix

* src: Correct error message for shardCount being imvalid

Co-Authored-By: bdistin <bdistin@gmail.com>

* src: Small tweaks

* src: If this doesn't fix the issues I'm gonna throw a brick at my PC

* src: I swear, STOP BREAKING

* src: *groans at a certain snake*

* src: Use undefined instead of null on destroy in close event

Setting it to null sets the close code to null, which causes a WebSocket error to be thrown. The error is thrown from WebSocket, although there is no connection alive. Fun times!

* src: @SpaceEEC's requested changes

* src: Remove zucc from discord.js

Discord is removing support for it, sooo... Bye bye

* src: Missed this

* src: Apply @kyranet's suggestions

Co-Authored-By: Antonio Román <kyradiscord@gmail.com>

* src: @kyranet's suggestions

* src: Remove pako, update debug messages
- Pako is officially gone from both enviroments
  Install zlib-sync on node.js if you want it
- Improve a few debug messages some more
- Discover that internal sharding works in browsers but please don't do that

typings/index.d.ts

@@ -1650,6 +1650,7 @@ declare module 'discord.js' {
 
 		public on(event: WSEventType, listener: (data: any, shardID: number) => void): this;
 		public once(event: WSEventType, listener: (data: any, shardID: number) => void): this;
+
 		private debug(message: string, shard?: WebSocketShard): void;
 		private connect(): Promise<void>;
 		private createShards(): Promise<void>;
@@ -1657,9 +1658,9 @@ declare module 'discord.js' {
 		private broadcast(packet: object): void;
 		private destroy(): void;
 		private _handleSessionLimit(remaining?: number, resetAfter?: number): Promise<void>;
-		private handlePacket(packet?: object, shard?: WebSocketShard): Promise<boolean>;
-		private checkReady(): boolean;
-		private triggerReady(): void;
+		private handlePacket(packet?: object, shard?: WebSocketShard): boolean;
+		private checkShardsReady(): Promise<void>;
+		private triggerClientReady(): void;
 	}
 
 	export class WebSocketShard extends EventEmitter {
@@ -1671,14 +1672,15 @@ declare module 'discord.js' {
 		private lastHeartbeatAcked: boolean;
 		private ratelimit: { queue: object[]; total: number; remaining: number; time: 60e3; timer: NodeJS.Timeout | null; };
 		private connection: WebSocket | null;
-		private helloTimeout: NodeJS.Timeout | null;
+		private helloTimeout: NodeJS.Timeout | undefined;
 		private eventsAttached: boolean;
+		private expectedGuilds: Set<Snowflake> | undefined;
+		private readyTimeout: NodeJS.Timeout | undefined;
 
 		public manager: WebSocketManager;
 		public id: number;
 		public status: Status;
-		public pings: [number, number, number];
-		public readonly ping: number;
+		public ping: number;
 
 		private debug(message: string): void;
 		private connect(): Promise<void>;
@@ -1687,6 +1689,7 @@ declare module 'discord.js' {
 		private onError(error: ErrorEvent | object): void;
 		private onClose(event: CloseEvent): void;
 		private onPacket(packet: object): void;
+		private checkReady(): void;
 		private setHelloTimeout(time?: number): void;
 		private setHeartbeatTimer(time: number): void;
 		private sendHeartbeat(): void;
@@ -1703,12 +1706,14 @@ declare module 'discord.js' {
 		public on(event: 'resumed', listener: () => void): this;
 		public on(event: 'close', listener: (event: CloseEvent) => void): this;
 		public on(event: 'invalidSession', listener: () => void): this;
+		public on(event: 'allReady', listener: (unavailableGuilds?: Set<Snowflake>) => void): this;
 		public on(event: string, listener: Function): this;
 
 		public once(event: 'ready', listener: () => void): this;
 		public once(event: 'resumed', listener: () => void): this;
 		public once(event: 'close', listener: (event: CloseEvent) => void): this;
 		public once(event: 'invalidSession', listener: () => void): this;
+		public once(event: 'allReady', listener: (unavailableGuilds?: Set<Snowflake>) => void): this;
 		public once(event: string, listener: Function): this;
 	}
 
@@ -2054,9 +2059,8 @@ declare module 'discord.js' {
 	}
 
 	interface ClientOptions {
-		shards?: number | number[];
-		shardCount?: number | 'auto';
-		totalShardCount?: number;
+		shards?: number | number[] | 'auto';
+		shardCount?: number;
 		messageCacheMaxSize?: number;
 		messageCacheLifetime?: number;
 		messageSweepInterval?: number;