@Nullable
    public String scope() {
        return scope;
    }
{@value OAuth2Constants#SCOPE} Token Introspection Response field,
OPTIONAL. A JSON string containing a space-separated list of scopes associated with this token,
in the format described at
<a href="https://datatracker.ietf.org/doc/html/rfc6749#section-3.3">[RFC6749], Section 3.3</a>.
oauth2/src/main/java/com/linecorp/armeria/common/auth/oauth2/OAuth2TokenDescriptor.java