@java.lang.Override
  public final boolean isInitialized() {
    byte isInitialized = memoizedIsInitialized;
    if (isInitialized == 1) return true;
    if (isInitialized == 0) return false;

    memoizedIsInitialized = 1;
    return true;
  }
<pre>
Payload.

The payload will be sent as the HTTP message body. A message
body, and thus a payload, is allowed only if the HTTP method is
POST or PUT. It is an error to set a data payload on a task with
an incompatible [HttpMethod][google.cloud.tasks.v2beta2.HttpMethod].
</pre>

<code>bytes payload = 5;</code>

@return The payload.
java-tasks/proto-google-cloud-tasks-v2beta2/src/main/java/com/google/cloud/tasks/v2beta2/AppEngineHttpRequest.java