Override BlockingPublisher Default Universe Domain

 namespace pubsub = ::google::cloud::pubsub; []() { google::cloud::Options options; // AddUniverseDomainOption interrogates the UnifiedCredentialsOption, if // set, in the provided Options for the Universe Domain associated with the // credentials and adds it to the set of Options. // If no UnifiedCredentialsOption is set, GoogleDefaultCredentials are used. auto ud_options = google::cloud::AddUniverseDomainOption(std::move(options)); if (!ud_options.ok()) throw std::move(ud_options).status(); auto pub = pubsub::BlockingPublisher(pubsub::MakeBlockingPublisherConnection( "europe-central2", *ud_options)); }