public Builder setGcsDataSource(
          com.google.storagetransfer.v1.proto.TransferTypes.GcsData.Builder builderForValue) {
        if (gcsDataSourceBuilder_ == null) {
          dataSource_ = builderForValue.build();
          onChanged();
        } else {
          gcsDataSourceBuilder_.setMessage(builderForValue.build());
        }
        dataSourceCase_ = 1;
        return this;
      }
<pre>
The Cloud Storage bucket from which to replicate objects.
</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