private com.google.protobuf.SingleFieldBuilderV3<
            com.google.protobuf.Timestamp,
            com.google.protobuf.Timestamp.Builder,
            com.google.protobuf.TimestampOrBuilder>
        getExpireTimeFieldBuilder() {
      if (expireTimeBuilder_ == null) {
        if (!(expirationCase_ == 2)) {
          expiration_ = com.google.protobuf.Timestamp.getDefaultInstance();
        }
        expireTimeBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.protobuf.Timestamp,
                com.google.protobuf.Timestamp.Builder,
                com.google.protobuf.TimestampOrBuilder>(
                (com.google.protobuf.Timestamp) expiration_, getParentForChildren(), isClean());
        expiration_ = null;
      }
      expirationCase_ = 2;
      onChanged();
      return expireTimeBuilder_;
    }
<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