public Builder mergeDuration(com.google.protobuf.Duration value) {
        if (durationBuilder_ == null) {
          if (((bitField0_ & 0x00000001) != 0)
              && duration_ != null
              && duration_ != com.google.protobuf.Duration.getDefaultInstance()) {
            getDurationBuilder().mergeFrom(value);
          } else {
            duration_ = value;
          }
        } else {
          durationBuilder_.mergeFrom(value);
        }
        if (duration_ != null) {
          bitField0_ |= 0x00000001;
          onChanged();
        }
        return this;
      }
<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