private com.google.protobuf.SingleFieldBuilderV3<
              com.google.protobuf.Duration,
              com.google.protobuf.Duration.Builder,
              com.google.protobuf.DurationOrBuilder>
          getDurationFieldBuilder() {
        if (durationBuilder_ == null) {
          durationBuilder_ =
              new com.google.protobuf.SingleFieldBuilderV3<
                  com.google.protobuf.Duration,
                  com.google.protobuf.Duration.Builder,
                  com.google.protobuf.DurationOrBuilder>(
                  getDuration(), getParentForChildren(), isClean());
          duration_ = null;
        }
        return durationBuilder_;
      }
<pre>
Duration of an ad opportunity. Must be greater than 0.
</pre>

<code>.google.protobuf.Duration duration = 1;</code>
java-video-live-stream/proto-google-cloud-live-stream-v1/src/main/java/com/google/cloud/video/livestream/v1/Event.java