public Builder clearPullMessage() {
      if (pullMessageBuilder_ == null) {
        if (payloadTypeCase_ == 13) {
          payloadTypeCase_ = 0;
          payloadType_ = null;
          onChanged();
        }
      } else {
        if (payloadTypeCase_ == 13) {
          payloadTypeCase_ = 0;
          payloadType_ = null;
        }
        pullMessageBuilder_.clear();
      }
      return this;
    }
<pre>
Pull Message contained in a task in a
[PULL][google.cloud.tasks.v2beta3.Queue.type] queue type. This payload
type cannot be explicitly set through Cloud Tasks API. Its purpose,
currently is to provide backward compatibility with App Engine Task Queue
[pull](https://cloud.google.com/appengine/docs/standard/java/taskqueue/pull/)
queues to provide a way to inspect contents of pull tasks through the
[CloudTasks.GetTask][google.cloud.tasks.v2beta3.CloudTasks.GetTask].
</pre>

<code>.google.cloud.tasks.v2beta3.PullMessage pull_message = 13;</code>
java-tasks/proto-google-cloud-tasks-v2beta3/src/main/java/com/google/cloud/tasks/v2beta3/Task.java