@java.lang.Override
  public com.google.protobuf.ByteString getMimeTypeBytes() {
    java.lang.Object ref = mimeType_;
    if (ref instanceof java.lang.String) {
      com.google.protobuf.ByteString b =
          com.google.protobuf.ByteString.copyFromUtf8((java.lang.String) ref);
      mimeType_ = b;
      return b;
    } else {
      return (com.google.protobuf.ByteString) ref;
    }
  }
<pre>
Optional. Can be "text/plain" or "text/html".
For `.tsv`, "text/html" is used if mime_type is missing.
For `.html`, this field must be "text/html" or empty.
For `.txt`, this field must be "text/plain" or empty.
</pre>

<code>string mime_type = 1 [(.google.api.field_behavior) = OPTIONAL];</code>

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