text: export function Canceler () {
    
    if (!(this instanceof Canceler)) return new Canceler()
  
    this.promise = new Promise(function cancelExecutor (resolve) {
      this.resolve = resolve
    }.bind(this))
  
  }
  
  
  Canceler.prototype.cancel = function (cancelSuccessCallback) {
    this.resolve(cancelSuccessCallback)
  }