public OAuth2TokenDescriptorBuilder expiresAt(Instant expiresAt) {
        this.expiresAt = requireNonNull(expiresAt, "expiresAt");
        return this;
    }
{@code exp} Token Introspection Response field,
OPTIONAL. {@link Instant} timestamp, indicating when this token will expire, as defined at
<a href="https://datatracker.ietf.org/doc/rfc7519/">[RFC7519]</a>.
oauth2/src/main/java/com/linecorp/armeria/common/auth/oauth2/OAuth2TokenDescriptorBuilder.java