public com.google.protobuf.ByteString getTargetLanguageCodeBytes() {
      java.lang.Object ref = targetLanguageCode_;
      if (ref instanceof String) {
        com.google.protobuf.ByteString b =
            com.google.protobuf.ByteString.copyFromUtf8((java.lang.String) ref);
        targetLanguageCode_ = b;
        return b;
      } else {
        return (com.google.protobuf.ByteString) ref;
      }
    }
<pre>
Required. The ISO-639 language code to use for translation of the input
document, set to one of the language codes listed in Language Support.
</pre>

<code>string target_language_code = 3 [(.google.api.field_behavior) = REQUIRED];</code>

@return The bytes for targetLanguageCode.
java-translate/proto-google-cloud-translate-v3/src/main/java/com/google/cloud/translate/v3/TranslateDocumentRequest.java