private void handleHeader(HeaderMap headers, IPolicyContext context, UniqueHeaderBean config) {
        String headerValue = null;
        if (!config.isOverwriteHeaderValue()) {
            headerValue = headers.get(config.getHeaderName());
        }
        if (StringUtils.isBlank(headerValue)) {
            headerValue = generateUniqueString();
        }
        headers.put(config.getHeaderName(), headerValue);
        context.setAttribute(UNIQUE_HEADER_KEY, headerValue);
    }
Handles the headers in regards to io.apiman.plugins.uniqueheader.beans.UniqueHeaderBean#isOverwriteHeader()
by overwriting the io.apiman.plugins.uniqueheader.beans.UniqueHeaderBean#getHeaderName() if the overwriteHeader
value is true
@param headers provided in the request
@param config the policy's configuration information
plugins/unique-header-policy/src/main/java/io/apiman/plugins/uniqueheader/UniqueHeaderPolicy.java