*Use once, not on

src/index.js

@@ -198,7 +198,7 @@ module.exports = function createTaskQueue(options) {
 				} else {
 					debugLoop(`Returning awaitDrained Promise for '${type}'`);
 					return new Promise((resolve, reject) => {
-						this.on(`queueDrained:${type}`, () => {
+						this.once(`queueDrained:${type}`, () => {
 							debugLoop(`Resolving awaitDrained Promise for '${type}'`);
 							resolve();
 						})
@@ -220,7 +220,7 @@ module.exports = function createTaskQueue(options) {
 				} else {
 					debugLoop(`Returning awaitCompleted Promise for '${type}'`);
 					return new Promise((resolve, reject) => {
-						this.on(`queueCompleted:${type}`, () => {
+						this.once(`queueCompleted:${type}`, () => {
 							debugLoop(`Resolving awaitCompleted Promise for '${type}'`);
 							resolve();
 						})