public Builder clearDuration() {
      bitField0_ = (bitField0_ & ~0x00000008);
      duration_ = null;
      if (durationBuilder_ != null) {
        durationBuilder_.dispose();
        durationBuilder_ = null;
      }
      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