public Builder setDuration(com.google.protobuf.Duration value) {
      if (durationBuilder_ == null) {
        if (value == null) {
          throw new NullPointerException();
        }
        duration_ = value;
      } else {
        durationBuilder_.setMessage(value);
      }
      bitField0_ |= 0x00000008;
      onChanged();
      return this;
    }
<pre>
Output only. Measures the duration of the execution.
</pre>

<code>.google.protobuf.Duration duration = 12 [(.google.api.field_behavior) = OUTPUT_ONLY];
</code>
java-workflow-executions/proto-google-cloud-workflow-executions-v1/src/main/java/com/google/cloud/workflows/executions/v1/Execution.java