@java.lang.Override
    public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
      if (dataSourceCase_ == 1) {
        output.writeMessage(
            1, (com.google.storagetransfer.v1.proto.TransferTypes.GcsData) dataSource_);
      }
      if (dataSinkCase_ == 2) {
        output.writeMessage(
            2, (com.google.storagetransfer.v1.proto.TransferTypes.GcsData) dataSink_);
      }
      if (((bitField0_ & 0x00000001) != 0)) {
        output.writeMessage(3, getObjectConditions());
      }
      if (((bitField0_ & 0x00000002) != 0)) {
        output.writeMessage(4, getTransferOptions());
      }
      getUnknownFields().writeTo(output);
    }
<pre>
Specifies the metadata options to be applied during replication.
Delete options are not supported. If a delete option is specified, the
request fails with an [INVALID_ARGUMENT][google.rpc.Code.INVALID_ARGUMENT]
error.
</pre>

<code>.google.storagetransfer.v1.TransferOptions transfer_options = 4;</code>
java-storage-transfer/proto-google-cloud-storage-transfer-v1/src/main/java/com/google/storagetransfer/v1/proto/TransferTypes.java