@Override
    public DefaultServiceConfigSetters errorHandler(ServiceErrorHandler serviceErrorHandler) {
        requireNonNull(serviceErrorHandler, "serviceErrorHandler");
        if (this.serviceErrorHandler == null) {
            this.serviceErrorHandler = serviceErrorHandler;
        } else {
            this.serviceErrorHandler = this.serviceErrorHandler.orElse(serviceErrorHandler);
        }
        return this;
    }
A default implementation of {@link ServiceConfigSetters} that stores service related settings
and provides a method {@link DefaultServiceConfigSetters#toServiceConfigBuilder(Route, String, HttpService)}
to build {@link ServiceConfigBuilder}.
core/src/main/java/com/linecorp/armeria/server/DefaultServiceConfigSetters.java