@java.lang.Override
    public com.google.protobuf.TimestampOrBuilder getExpireTimeOrBuilder() {
      if ((expirationCase_ == 2) && (expireTimeBuilder_ != null)) {
        return expireTimeBuilder_.getMessageOrBuilder();
      } else {
        if (expirationCase_ == 2) {
          return (com.google.protobuf.Timestamp) expiration_;
        }
        return com.google.protobuf.Timestamp.getDefaultInstance();
      }
    }
<pre>
Desired expiration time of the access token. This value must
be at most 24 hours in the future. If a value is not specified, the
token's expiration time will be set to a default value of 1 hour in the
future.
</pre>

<code>.google.protobuf.Timestamp expire_time = 2;</code>
java-workstations/proto-google-cloud-workstations-v1beta/src/main/java/com/google/cloud/workstations/v1beta/GenerateAccessTokenRequest.java