code: function BehaviorSubject(value) {
      __super__.call(this, subscribe);
      this.value = value,
      this.observers = [],
      this.isDisposed = false,
      this.isStopped = false,
      this.hasError = false;
    }
docs: Initializes a new instance of the BehaviorSubject class which creates a subject that caches its last value and starts with the specified value.
  @param {Mixed} value Initial value sent to observers when no other value has been received by the subject yet.