private com.google.protobuf.SingleFieldBuilderV3<
              com.google.type.Interval,
              com.google.type.Interval.Builder,
              com.google.type.IntervalOrBuilder>
          getValidIntervalFieldBuilder() {
        if (validIntervalBuilder_ == null) {
          if (!(startTimingConstraintsCase_ == 5)) {
            startTimingConstraints_ = com.google.type.Interval.getDefaultInstance();
          }
          validIntervalBuilder_ =
              new com.google.protobuf.SingleFieldBuilderV3<
                  com.google.type.Interval,
                  com.google.type.Interval.Builder,
                  com.google.type.IntervalOrBuilder>(
                  (com.google.type.Interval) startTimingConstraints_,
                  getParentForChildren(),
                  isClean());
          startTimingConstraints_ = null;
        }
        startTimingConstraintsCase_ = 5;
        onChanged();
        return validIntervalBuilder_;
      }
<pre>
An absolute time interval within which resources may be created.
</pre>

<code>.google.type.Interval valid_interval = 5;</code>
java-tpu/proto-google-cloud-tpu-v2alpha1/src/main/java/com/google/cloud/tpu/v2alpha1/QueuedResource.java