public final void serialize(OutputStream out) throws IOException {
        out.write(Jackson.toJsonString(this).getBytes(UTF8));
        out.flush();
    }
Writes the serialized representation of the paused transfer state to the
given <code>OutputStream</code>. Caller of this method should explicitly
close the <code>OutputStream</code>.
aws-java-sdk-s3/src/main/java/com/amazonaws/services/s3/transfer/PersistableTransfer.java