private com.google.protobuf.SingleFieldBuilderV3<
              com.google.protobuf.Duration,
              com.google.protobuf.Duration.Builder,
              com.google.protobuf.DurationOrBuilder>
          getTravelDurationFieldBuilder() {
        if (travelDurationBuilder_ == null) {
          travelDurationBuilder_ =
              new com.google.protobuf.SingleFieldBuilderV3<
                  com.google.protobuf.Duration,
                  com.google.protobuf.Duration.Builder,
                  com.google.protobuf.DurationOrBuilder>(
                  getTravelDuration(), getParentForChildren(), isClean());
          travelDuration_ = null;
        }
        return travelDurationBuilder_;
      }
<pre>
The number of seconds required to travel to the job location from the
query location. A duration of 0 seconds indicates that the job isn't
reachable within the requested duration, but was returned as part of an
expanded query.
</pre>

<code>.google.protobuf.Duration travel_duration = 2;</code>
java-talent/proto-google-cloud-talent-v4beta1/src/main/java/com/google/cloud/talent/v4beta1/SearchJobsResponse.java