@Override
    public byte[] unmarshall(InputStream input) throws Exception {
        try (ByteArrayOutputStream output = new ByteArrayOutputStream()) {
            IOUtils.copy(input, output);
            output.flush();
            return output.toByteArray();
        }
    }
@see io.apiman.gateway.engine.io.IPayloadIO#unmarshall(java.io.InputStream)
gateway/engine/core/src/main/java/io/apiman/gateway/engine/io/BytesPayloadIO.java