avoid using the cached timeouts unless neccisary

browser.js

@@ -1,5 +1,4 @@
 // shim for using process in browser
-
 var process = module.exports = {};
 
 // cached from whatever global is present so that test runners that stub it
@@ -11,21 +10,35 @@ var cachedSetTimeout;
 var cachedClearTimeout;
 
 (function () {
-  try {
-    cachedSetTimeout = setTimeout;
-  } catch (e) {
-    cachedSetTimeout = function () {
-      throw new Error('setTimeout is not defined');
+    try {
+        cachedSetTimeout = setTimeout;
+    } catch (e) {
+        cachedSetTimeout = function () {
+            throw new Error('setTimeout is not defined');
+        }
     }
-  }
-  try {
-    cachedClearTimeout = clearTimeout;
-  } catch (e) {
-    cachedClearTimeout = function () {
-      throw new Error('clearTimeout is not defined');
+    try {
+        cachedClearTimeout = clearTimeout;
+    } catch (e) {
+        cachedClearTimeout = function () {
+            throw new Error('clearTimeout is not defined');
+        }
     }
-  }
 } ())
+function runTimeout(fun) {
+    if (cachedSetTimeout === setTimeout) {
+        return setTimeout(fun, 0);
+    } else {
+        return cachedSetTimeout.call(null, fun, 0);
+    }
+}
+function runClearTimeout(marker) {
+    if (cachedClearTimeout === clearTimeout) {
+        clearTimeout(marker);
+    } else {
+        cachedClearTimeout.call(null, marker);
+    }
+}
 var queue = [];
 var draining = false;
 var currentQueue;
@@ -50,7 +63,7 @@ function drainQueue() {
     if (draining) {
         return;
     }
-    var timeout = cachedSetTimeout.call(null, cleanUpNextTick);
+    var timeout = runTimeout(cleanUpNextTick);
     draining = true;
 
     var len = queue.length;
@@ -67,7 +80,7 @@ function drainQueue() {
     }
     currentQueue = null;
     draining = false;
-    cachedClearTimeout.call(null, timeout);
+    runClearTimeout(timeout);
 }
 
 process.nextTick = function (fun) {
@@ -79,7 +92,7 @@ process.nextTick = function (fun) {
     }
     queue.push(new Item(fun, args));
     if (queue.length === 1 && !draining) {
-        cachedSetTimeout.call(null, drainQueue, 0);
+        runTimeout(drainQueue);
     }
 };