Storage Control Update Anywhere Cache

namespace storagecontrol = google::cloud::storagecontrol_v2;
[](storagecontrol::StorageControlClient client, std::string const& cache_name,
   std::string const& admission_policy) {
  google::storage::control::v2::AnywhereCache cache;
  google::protobuf::FieldMask field_mask;
  field_mask.add_paths("admission_policy");
  cache.set_name(cache_name);
  cache.set_admission_policy(admission_policy);
  // Start an update operation and block until it completes. Real applications
  // may want to setup a callback, wait on a coroutine, or poll until it
  // completes.
  auto anywhere_cache = client.UpdateAnywhereCache(cache, field_mask).get();
  if (!anywhere_cache) throw std::move(anywhere_cache).status();
  std::cout << "Updated anywhere cache: " << anywhere_cache->name() << "\n";
}