Add support for max_concurrency

Author: Brainicism

index.d.ts

@@ -291,6 +291,7 @@ declare namespace Eris {
     rest?: RequestHandlerOptions;
     restMode?: boolean;
     seedVoiceConnections?: boolean;
+    useMaxConcurrency?: boolean;
     ws?: unknown;
   }
   interface CommandClientOptions {

lib/Client.js

@@ -148,6 +148,7 @@ class Client extends EventEmitter {
             rest: {},
             restMode: false,
             seedVoiceConnections: false,
+            useMaxConcurrency: false,
             ws: {},
             reconnectDelay: (lastDelay, attempts) => Math.pow(attempts + 1, 0.7) * 20000
         }, options);

lib/gateway/ShardManager.js

@@ -8,14 +8,14 @@ class ShardManager extends Collection {
     constructor(client) {
         super(Shard);
         this._client = client;
-
+        this.maxConcurrency = 1;
         this.connectQueue = [];
         this.lastConnect = 0;
         this.connectTimeout = null;
     }
 
     connect(shard) {
-        if(shard.sessionID || (this.lastConnect <= Date.now() - 5000 && !this.find((shard) => shard.connecting))) {
+        if((shard.sessionID || (this.lastConnect <= Date.now() - 5000 && !this.find((shard) => shard.connecting))) && !this._client.options.useMaxConcurrency) {
             shard.connect();
             this.lastConnect = Date.now() + 7500;
         } else {
@@ -95,17 +95,31 @@ class ShardManager extends Collection {
         }
     }
 
+    // https://github.com/curtisf/eris/commit/6b8397da17c2fabf37f5c08f40899c5131d599fb#diff-df83f51ebdee7648e64537556e67de936a1f8a78c2e4459b49a5b850a35cdfa2
     tryConnect() {
         if(this.connectQueue.length > 0) {
-            if(this.lastConnect <= Date.now() - 5000) {
-                const shard = this.connectQueue.shift();
-                shard.connect();
-                this.lastConnect = Date.now() + 7500;
-            } else if(!this.connectTimeout) {
-                this.connectTimeout = setTimeout(() => {
-                    this.connectTimeout = null;
-                    this.tryConnect();
-                }, 1000);
+            if(!this._client.options.useMaxConcurrency) {
+                if(this.lastConnect <= Date.now() - 5000) {
+                    const shard = this.connectQueue.shift();
+                    shard.connect();
+                    this.lastConnect = Date.now() + 7500;
+                } else if(!this.connectTimeout) {
+                    this.connectTimeout = setTimeout(() => {
+                        this.connectTimeout = null;
+                        this.tryConnect();
+                    }, 1000);
+                }
+            } else {
+                if(this.filter((shard) => shard.connecting).length < this.maxConcurrency) {
+                    const shard = this.connectQueue.shift();
+                    shard.connect();
+                    //this.lastConnect = Date.now() + 7500;
+                } else if(!this.connectTimeout) {
+                    this.connectTimeout = setTimeout(() => {
+                        this.connectTimeout = null;
+                        this.tryConnect();
+                    }, 250);
+                }
             }
         }
     }