private com.google.protobuf.SingleFieldBuilderV3<
              com.google.protobuf.Duration,
              com.google.protobuf.Duration.Builder,
              com.google.protobuf.DurationOrBuilder>
          getValidAfterDurationFieldBuilder() {
        if (validAfterDurationBuilder_ == null) {
          if (!(startTimingConstraintsCase_ == 3)) {
            startTimingConstraints_ = com.google.protobuf.Duration.getDefaultInstance();
          }
          validAfterDurationBuilder_ =
              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_ = 3;
        onChanged();
        return validAfterDurationBuilder_;
      }
<pre>
A relative time after which resources may be created.
</pre>

<code>.google.protobuf.Duration valid_after_duration = 3;</code>
java-tpu/proto-google-cloud-tpu-v2alpha1/src/main/java/com/google/cloud/tpu/v2alpha1/QueuedResource.java