public Builder setOauthToken(com.google.cloud.tasks.v2beta2.OAuthToken value) {
      if (oauthTokenBuilder_ == null) {
        if (value == null) {
          throw new NullPointerException();
        }
        authorizationHeader_ = value;
        onChanged();
      } else {
        oauthTokenBuilder_.setMessage(value);
      }
      authorizationHeaderCase_ = 5;
      return this;
    }
<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.v2beta2.OAuthToken oauth_token = 5;</code>
java-tasks/proto-google-cloud-tasks-v2beta2/src/main/java/com/google/cloud/tasks/v2beta2/HttpTarget.java