public Builder setExecutionHistoryLevel(
        com.google.cloud.workflows.v1.ExecutionHistoryLevel value) {
      if (value == null) {
        throw new NullPointerException();
      }
      bitField0_ |= 0x00004000;
      executionHistoryLevel_ = value.getNumber();
      onChanged();
      return this;
    }
<pre>
Optional. Describes the execution history level to apply to this workflow.
</pre>

<code>
.google.cloud.workflows.v1.ExecutionHistoryLevel execution_history_level = 15 [(.google.api.field_behavior) = OPTIONAL];
</code>

@param value The executionHistoryLevel to set.
@return This builder for chaining.
java-workflows/proto-google-cloud-workflows-v1/src/main/java/com/google/cloud/workflows/v1/Workflow.java