code: @Nonnull
    public static AuthIdentificationResult createFailure (@Nonnull final ICredentialValidationResult aCredentialValidationFailure)
    {
      ValueEnforcer.notNull (aCredentialValidationFailure, "CredentialValidationFailure");
      return new AuthIdentificationResult (null, aCredentialValidationFailure);
    }
docs: Factory method for error in authentication.
  
  @param aCredentialValidationFailure
  The validation failure. May not be <code>null</code> in case of
  failure!
  @return Never <code>null</code>.