@Override
    public Collection<Form> getUserAttributes() {

        // Add any custom attributes to any previously defined attributes
        return Collections.unmodifiableCollection(Stream.concat(
                super.getUserAttributes().stream(),
                attributeService.getUserAttributes().stream()
        ).collect(Collectors.toList()));

    }
Retrieves the GuacamoleConfiguration of the given Connection. If
possible, privileged access to the configuration is obtained first. Note
that the underlying extension is not required to allow privileged
access, nor is it required to expose the underlying configuration at
all.

@param connection
    The connection to retrieve the configuration from.

@return
    The GuacamoleConfiguration associated with the given connection,
    which may be partial or empty.

@throws GuacamoleException
    If an error prevents privileged retrieval of the configuration.
extensions/guacamole-vault/modules/guacamole-vault-base/src/main/java/org/apache/guacamole/vault/user/VaultUserContext.java