public Builder mergeStartTimeOffset(com.google.protobuf.Duration value) {
        if (startTimeOffsetBuilder_ == null) {
          if (((bitField0_ & 0x00000004) != 0)
              && startTimeOffset_ != null
              && startTimeOffset_ != com.google.protobuf.Duration.getDefaultInstance()) {
            getStartTimeOffsetBuilder().mergeFrom(value);
          } else {
            startTimeOffset_ = value;
          }
        } else {
          startTimeOffsetBuilder_.mergeFrom(value);
        }
        if (startTimeOffset_ != null) {
          bitField0_ |= 0x00000004;
          onChanged();
        }
        return this;
      }
<pre>
The time to start the fade animation, in seconds. Default: 0
</pre>

<code>.google.protobuf.Duration start_time_offset = 3;</code>
java-video-transcoder/proto-google-cloud-video-transcoder-v1/src/main/java/com/google/cloud/video/transcoder/v1/Overlay.java