public ServiceRequestContextBuilder defaultServiceName(String defaultServiceName) {
        requireNonNull(defaultServiceName, "defaultServiceName");
        return defaultServiceNaming(ServiceNaming.of(defaultServiceName));
    }
Sets the default value of the {@link RequestLog#serviceName()} property which is used when
no service name was set via {@link RequestLogBuilder#name(String, String)}.

@param defaultServiceName the default log name.
core/src/main/java/com/linecorp/armeria/server/ServiceRequestContextBuilder.java