public void append(AbstractUtf8Array v) throws IOException {
        final int length = v.getByteLength();
        if (shouldCopy(length)) {
            makeRoom(length);
            v.writeTo(current);
        } else {
            append(v.wrap());
        }
    }
Data store for AbstractByteWriter. Tested in unit tests for ByteWriter.

@author Steinar Knutsen
vespajlib/src/main/java/com/yahoo/io/BufferChain.java