
    var callCount4 = 0;
    var callCount5 = 0;
    var callback1 = function() {
      callCount1++;
    };
    var callback2 = function() {
      callCount2++;
      throw new Error('intentional error 1');
    };
    var callback3 = function() {
      callCount3++;
      microTask.run(callback5);
      throw new Error('intentional error 2');
    };
    var callback4 = function() {
      callCount4++;
    };
    var callback5 = function() {
      callCount5++;
    };
    microTask.run(callback1);
    micro