presto-spi/src/main/java/io/prestosql/spi/security/Identity.java/Identity/Identity
class Identity:    @Deprecated
    public Identity(String user, Optional<Principal> principal, Map<String, SelectedRole> roles, Map<String, String> extraCredentials)
    {
        this.user = requireNonNull(user, "user is null");
        this.principal = requireNonNull(principal, "principal is null");
        this.roles = unmodifiableMap(new HashMap<>(requireNonNull(roles, "roles is null")));
        this.extraCredentials = unmodifiableMap(new HashMap<>(requireNonNull(extraCredentials, "extraCredentials is null")));
    }