private com.google.protobuf.SingleFieldBuilderV3<
              com.google.protobuf.Duration,
              com.google.protobuf.Duration.Builder,
              com.google.protobuf.DurationOrBuilder>
          getValidUntilDurationFieldBuilder() {
        if (validUntilDurationBuilder_ == null) {
          if (!(startTimingConstraintsCase_ == 1)) {
            startTimingConstraints_ = com.google.protobuf.Duration.getDefaultInstance();
          }
          validUntilDurationBuilder_ =
              new com.google.protobuf.SingleFieldBuilderV3<
                  com.google.protobuf.Duration,
                  com.google.protobuf.Duration.Builder,
                  com.google.protobuf.DurationOrBuilder>(
                  (com.google.protobuf.Duration) startTimingConstraints_,
                  getParentForChildren(),
                  isClean());
          startTimingConstraints_ = null;
        }
        startTimingConstraintsCase_ = 1;
        onChanged();
        return validUntilDurationBuilder_;
      }
<pre>
Optional. A relative time after which resources should not be created.
If the request cannot be fulfilled by this time the request will be
failed.
</pre>

<code>
.google.protobuf.Duration valid_until_duration = 1 [(.google.api.field_behavior) = OPTIONAL];
</code>
java-tpu/proto-google-cloud-tpu-v2/src/main/java/com/google/cloud/tpu/v2/QueuedResource.java