private boolean isFailureTolerated() {
        return tolerateFailures.contains(getIdentifier());
    }
Returns whether this authentication provider should tolerate internal
failures during the authentication process, allowing other
authentication providers to continue operating as if this authentication
provider simply is not present.

@return
    true if this authentication provider should tolerate internal
    failures during the authentication process, false otherwise.
guacamole/src/main/java/org/apache/guacamole/extension/AuthenticationProviderFacade.java