public com.google.protobuf.Duration.Builder getTaskTtlBuilder() {
      bitField0_ |= 0x00000080;
      onChanged();
      return getTaskTtlFieldBuilder().getBuilder();
    }
<pre>
The maximum amount of time that a task will be retained in
this queue.

Queues created by Cloud Tasks have a default `task_ttl` of 31 days.
After a task has lived for `task_ttl`, the task will be deleted
regardless of whether it was dispatched or not.

The `task_ttl` for queues created via queue.yaml/xml is equal to the
maximum duration because there is a
[storage quota](https://cloud.google.com/appengine/quotas#Task_Queue) for
these queues. To view the maximum valid duration, see the documentation for
[Duration][google.protobuf.Duration].
</pre>

<code>.google.protobuf.Duration task_ttl = 8;</code>
java-tasks/proto-google-cloud-tasks-v2beta3/src/main/java/com/google/cloud/tasks/v2beta3/Queue.java