public Builder clearApiVersion() {
      apiVersion_ = getDefaultInstance().getApiVersion();
      bitField0_ = (bitField0_ & ~0x00000020);
      onChanged();
      return this;
    }
<pre>
Output only. API version used to start the operation.
</pre>

<code>string api_version = 6 [(.google.api.field_behavior) = OUTPUT_ONLY];</code>

@return This builder for chaining.
java-video-live-stream/proto-google-cloud-live-stream-v1/src/main/java/com/google/cloud/video/livestream/v1/OperationMetadata.java