public HealthCheckServiceBuilder updatable(boolean updatable) {
        if (updatable) {
            return updatable(HealthCheckUpdateHandler.of());
        }

        updateHandler = null;
        return this;
    }
Specifies whether the healthiness of the {@link Server} can be updated by sending a {@code PUT},
{@code POST} or {@code PATCH} request to the {@link HealthCheckService}. This feature is disabled
by default. If enabled, a JSON object which has a boolean property named {@code "healthy"} can be
sent using a {@code PUT} or {@code POST} request. A JSON patch in a {@code PATCH} request is also
accepted. It is recommended to employ some authorization mechanism such as {@link AuthService}
when enabling this feature.

@return {@code this}
@see #updatable(HealthCheckUpdateHandler)
@see HealthCheckUpdateHandler#of()
core/src/main/java/com/linecorp/armeria/server/healthcheck/HealthCheckServiceBuilder.java