private com.google.protobuf.SingleFieldBuilderV3<
              com.google.storagetransfer.v1.proto.TransferTypes.AwsS3CompatibleData,
              com.google.storagetransfer.v1.proto.TransferTypes.AwsS3CompatibleData.Builder,
              com.google.storagetransfer.v1.proto.TransferTypes.AwsS3CompatibleDataOrBuilder>
          getAwsS3CompatibleDataSourceFieldBuilder() {
        if (awsS3CompatibleDataSourceBuilder_ == null) {
          if (!(dataSourceCase_ == 19)) {
            dataSource_ =
                com.google.storagetransfer.v1.proto.TransferTypes.AwsS3CompatibleData
                    .getDefaultInstance();
          }
          awsS3CompatibleDataSourceBuilder_ =
              new com.google.protobuf.SingleFieldBuilderV3<
                  com.google.storagetransfer.v1.proto.TransferTypes.AwsS3CompatibleData,
                  com.google.storagetransfer.v1.proto.TransferTypes.AwsS3CompatibleData.Builder,
                  com.google.storagetransfer.v1.proto.TransferTypes.AwsS3CompatibleDataOrBuilder>(
                  (com.google.storagetransfer.v1.proto.TransferTypes.AwsS3CompatibleData)
                      dataSource_,
                  getParentForChildren(),
                  isClean());
          dataSource_ = null;
        }
        dataSourceCase_ = 19;
        onChanged();
        return awsS3CompatibleDataSourceBuilder_;
      }
<pre>
An AWS S3 compatible data source.
</pre>

<code>.google.storagetransfer.v1.AwsS3CompatibleData aws_s3_compatible_data_source = 19;
</code>
java-storage-transfer/proto-google-cloud-storage-transfer-v1/src/main/java/com/google/storagetransfer/v1/proto/TransferTypes.java