public com.google.storagetransfer.v1.proto.TransferTypes.GcsData.Builder
          getGcsDataSourceBuilder() {
        return getGcsDataSourceFieldBuilder().getBuilder();
      }
<pre>
A Cloud Storage data source.
</pre>

<code>.google.storagetransfer.v1.GcsData gcs_data_source = 1;</code>
java-storage-transfer/proto-google-cloud-storage-transfer-v1/src/main/java/com/google/storagetransfer/v1/proto/TransferTypes.java