@java.lang.Override
  public com.google.cloud.tasks.v2beta3.OAuthTokenOrBuilder getOauthTokenOrBuilder() {
    if (authorizationHeaderCase_ == 5) {
      return (com.google.cloud.tasks.v2beta3.OAuthToken) authorizationHeader_;
    }
    return com.google.cloud.tasks.v2beta3.OAuthToken.getDefaultInstance();
  }
<pre>
If specified, an
[OAuth token](https://developers.google.com/identity/protocols/OAuth2)
will be generated and attached as an `Authorization` header in the HTTP
request.

This type of authorization should generally only be used when calling
Google APIs hosted on *.googleapis.com.
</pre>

<code>.google.cloud.tasks.v2beta3.OAuthToken oauth_token = 5;</code>
java-tasks/proto-google-cloud-tasks-v2beta3/src/main/java/com/google/cloud/tasks/v2beta3/HttpRequest.java