class UserGroupInformation {

  @InterfaceAudience.Private
  @InterfaceStability.Unstable
  @VisibleForTesting
  public static void setLoginUser(UserGroupInformation ugi) {
    // if this is to become stable, should probably logout the currently
    // logged in ugi if it's different
    loginUserRef.set(ugi);
  }

    UserGroupInformation(Subject subject);

}