@Override
        public void send(ByteBuffer src) throws IOException {
            if (buffers.containsKey(src)) {
                throw new IOException(RECYCLED_BYTE_BUFFER);
            } else {
                buffers.put(src, null);
            }
        }
A stream which does nothing, but complains if it is called and asked to
do nothing.
vespajlib/src/test/java/com/yahoo/io/ByteWriterTestCase.java