private com.google.protobuf.SingleFieldBuilderV3<
              com.google.storagetransfer.v1.proto.TransferTypes.S3CompatibleMetadata,
              com.google.storagetransfer.v1.proto.TransferTypes.S3CompatibleMetadata.Builder,
              com.google.storagetransfer.v1.proto.TransferTypes.S3CompatibleMetadataOrBuilder>
          getS3MetadataFieldBuilder() {
        if (s3MetadataBuilder_ == null) {
          if (!(dataProviderCase_ == 4)) {
            dataProvider_ =
                com.google.storagetransfer.v1.proto.TransferTypes.S3CompatibleMetadata
                    .getDefaultInstance();
          }
          s3MetadataBuilder_ =
              new com.google.protobuf.SingleFieldBuilderV3<
                  com.google.storagetransfer.v1.proto.TransferTypes.S3CompatibleMetadata,
                  com.google.storagetransfer.v1.proto.TransferTypes.S3CompatibleMetadata.Builder,
                  com.google.storagetransfer.v1.proto.TransferTypes.S3CompatibleMetadataOrBuilder>(
                  (com.google.storagetransfer.v1.proto.TransferTypes.S3CompatibleMetadata)
                      dataProvider_,
                  getParentForChildren(),
                  isClean());
          dataProvider_ = null;
        }
        dataProviderCase_ = 4;
        onChanged();
        return s3MetadataBuilder_;
      }
<pre>
A S3 compatible metadata.
</pre>

<code>.google.storagetransfer.v1.S3CompatibleMetadata s3_metadata = 4;</code>
java-storage-transfer/proto-google-cloud-storage-transfer-v1/src/main/java/com/google/storagetransfer/v1/proto/TransferTypes.java