Remove finally polyfill

Author: moonglum

lib/runner.js

@@ -7,7 +7,7 @@ exports.SerializedRunner = class SerializedRunner {
 
 	run(...args) {
 		if(!this._pending) { // prevent concurrent execution
-			this._pending = augment(this.asyncOp(...args)).
+			this._pending = this.asyncOp(...args).
 				finally(() => {
 					this._pending = null;
 				});
@@ -24,7 +24,7 @@ exports.SerializedRunner = class SerializedRunner {
 		let enqueue = this._pending;
 		let res = this.run(...args);
 		if(enqueue) {
-			this._queued = res = augment(res).
+			this._queued = res = res.
 				finally(() => {
 					this._queued = null;
 				}).
@@ -33,20 +33,3 @@ exports.SerializedRunner = class SerializedRunner {
 		return res;
 	}
 };
-
-function augment(promise) {
-	promise.finally = always;
-	return promise;
-}
-
-// poor man's `Promise#finally` polyfill
-function always(fn) {
-	return this.
-		then(res => {
-			fn();
-			return res;
-		}, err => {
-			fn();
-			throw err;
-		});
-}