public void write(IApimanBuffer chunk) {
        if (fileOS == null) {
            try {
                fileOS = new FileOutputStream(tmpFile);
                fileOS.write(chunk.getBytes());
            } catch (IOException e) {
                // TODO: Log the error.
                // The response will not be cached as it might not contain a valid body
                writeFailed = true;
            }
        }
    }
This class aims to embody all the data related to a API response. The instance will contain
the response headers, code, message and body. The body will be persisted as a file in a temporary
folder

@author rubenrm1@gmail.com
gateway/engine/core/src/main/java/io/apiman/gateway/engine/impl/CachedResponse.java