public Builder clearGcsSource() {
        if (gcsSourceBuilder_ == null) {
          if (sourceCase_ == 3) {
            sourceCase_ = 0;
            source_ = null;
            onChanged();
          }
        } else {
          if (sourceCase_ == 3) {
            sourceCase_ = 0;
            source_ = null;
          }
          gcsSourceBuilder_.clear();
        }
        return this;
      }
<pre>
Google Cloud Storage file source.
</pre>

<code>.google.cloud.translation.v3.GcsInputSource gcs_source = 3;</code>
java-translate/proto-google-cloud-translate-v3/src/main/java/com/google/cloud/translate/v3/DatasetInputConfig.java