public Builder mergeRetryConfig(com.google.cloud.tasks.v2beta3.RetryConfig value) {
      if (retryConfigBuilder_ == null) {
        if (((bitField0_ & 0x00000010) != 0)
            && retryConfig_ != null
            && retryConfig_ != com.google.cloud.tasks.v2beta3.RetryConfig.getDefaultInstance()) {
          getRetryConfigBuilder().mergeFrom(value);
        } else {
          retryConfig_ = value;
        }
      } else {
        retryConfigBuilder_.mergeFrom(value);
      }
      if (retryConfig_ != null) {
        bitField0_ |= 0x00000010;
        onChanged();
      }
      return this;
    }
<pre>
Settings that determine the retry behavior.

* For tasks created using Cloud Tasks: the queue-level retry settings
  apply to all tasks in the queue that were created using Cloud Tasks.
  Retry settings cannot be set on individual tasks.
* For tasks created using the App Engine SDK: the queue-level retry
  settings apply to all tasks in the queue which do not have retry settings
  explicitly set on the task and were created by the App Engine SDK. See
  [App Engine
  documentation](https://cloud.google.com/appengine/docs/standard/python/taskqueue/push/retrying-tasks).
</pre>

<code>.google.cloud.tasks.v2beta3.RetryConfig retry_config = 5;</code>
java-tasks/proto-google-cloud-tasks-v2beta3/src/main/java/com/google/cloud/tasks/v2beta3/Queue.java