"use strict";
  var util = require("./util");
  var schedule;
  var noAsyncScheduler = function() {
      throw new Error("No async scheduler available\u000a\u000a    See http://goo.gl/MqrFmX\u000a");
  };
  var NativePromise = util.getNativePromise();
  if (util.isNode && typeof MutationObserver === "undefined") {
      var GlobalSetImmediate = global.setImmediate;
      var ProcessNextTick = process.nextTick;
      schedule = util.isRecentNode
                  ? function(fn) { GlobalSetImmediate.call(global, fn); }
                  : function(fn) { ProcessNextTick.call(process, fn); };
  } else if (typeof NativePromise === "function" &&
             typeof NativePromise.resolve === "function") {
      var nativePromise = NativePromise.resolve();
      schedule = function(fn) {
          nativePromise.then(fn);
      };
  } else if ((typeof MutationObserver !== "undefined") &&
            !(typeof window !== "undefined" &&
              window.navigator &&
              (window.navigator.standalone || window.cordova))) {
      schedule = (function() {
          var div = document.createElement("div");
          var opts = {attributes: true};
          var toggleScheduled = false;
          var div2 = document.createElement("div");
          var o2 = new MutationObserver(function() {
              div.classList.toggle("foo");
              toggleScheduled = false;
          });
          o2.observe(div2, opts);
  
          var scheduleToggle = function() {
              if (toggleScheduled) return;
              toggleScheduled = true;
              div2.classList.toggle("foo");
          };
  
          return function schedule(fn) {
              var o = new MutationObserver(function() {
                  o.disconnect();
                  fn();
              });
              o.observe(div, opts);
              scheduleToggle();
          };
      })();
  } else if (typeof setImmediate !== "undefined") {
      schedule = function (fn) {
          setImmediate(fn);
      };
  } else if (typeof setTimeout !== "undefined") {
      schedule = function (fn) {
          setTimeout(fn, 0);
      };
  } else {
      schedule = noAsyncScheduler;
  }
  module.exports = schedule;