public Builder clearExpireTime() {
      if (expireTimeBuilder_ == null) {
        if (expirationCase_ == 13) {
          expirationCase_ = 0;
          expiration_ = null;
          onChanged();
        }
      } else {
        if (expirationCase_ == 13) {
          expirationCase_ = 0;
          expiration_ = null;
        }
        expireTimeBuilder_.clear();
      }
      return this;
    }
<pre>
Non-empty default. The timestamp in UTC when the subscription expires.
Always displayed on output, regardless of what was used on input.
</pre>

<code>
.google.protobuf.Timestamp expire_time = 13 [(.google.api.field_behavior) = NON_EMPTY_DEFAULT];
</code>
java-workspaceevents/proto-google-cloud-workspaceevents-v1/src/main/java/com/google/apps/events/subscriptions/v1/Subscription.java