@Deprecated
    public Builder setApiKey(String apiKey) {
      this.apiKey = apiKey;
      return this;
    }
Sets the API key used to issue requests. This will be ignored if credentials are explicitly
set with {@link ServiceOptions.Builder#setCredentials setCredentials}. If neither are set,
and no Application Default Credentials are available, an API key is looked for in the {@code
GOOGLE_API_KEY} environment variable. For instructions on how to get an API key, see the <a
href="https://cloud.google.com/translate/v2/quickstart">Translate Quickstart</a>.
java-translate/google-cloud-translate/src/main/java/com/google/cloud/translate/TranslateOptions.java