public Builder mergeDwellStartTime(com.google.protobuf.Timestamp value) {
        if (dwellStartTimeBuilder_ == null) {
          if (((bitField0_ & 0x00000004) != 0)
              && dwellStartTime_ != null
              && dwellStartTime_ != com.google.protobuf.Timestamp.getDefaultInstance()) {
            getDwellStartTimeBuilder().mergeFrom(value);
          } else {
            dwellStartTime_ = value;
          }
        } else {
          dwellStartTimeBuilder_.mergeFrom(value);
        }
        if (dwellStartTime_ != null) {
          bitField0_ |= 0x00000004;
          onChanged();
        }
        return this;
      }
<pre>
The beginning time when a dwelling object has been identified in a zone.
</pre>

<code>.google.protobuf.Timestamp dwell_start_time = 3;</code>
java-visionai/proto-google-cloud-visionai-v1/src/main/java/com/google/cloud/visionai/v1/OccupancyCountingPredictionResult.java