  end() {
    if (this._sock && this._sock.writable) {
      this._protocol.disconnect(DISCONNECT_REASON.BY_APPLICATION);
      this._sock.end();
    }
    return this;
  }
The software constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.