in spectator/registry.h [337:343]
explicit SpectatordRegistry(const Config& config, logger_ptr logger)
: base_registry<stateless<stateless_types<SpectatordPublisher>>>(
std::move(logger)) {
extra_tags_ = Tags::from(config.common_tags);
state_.publisher =
std::make_unique<SpectatordPublisher>(config.endpoint, config.bytes_to_buffer, logger_);
}