*Check if socket exists before closing to prevent errors on possible race conditions

src/index.ts

@@ -150,8 +150,12 @@ export class Socket extends EventEmitter {
   }
 
   end(): void {
+    callModule(DHT_MODULE, "socketExists", { id: this.id }).then(([exists]: ErrTuple) => {
+      if (exists) {
         callModule(DHT_MODULE, "close", { id: this.id });
       }
+    });
+  }
 
   private ensureEvent(event: string): void {
     if (!(event in this.eventUpdates)) {