public void addHeader(String name, String value) {
        headers.put(name, value);

        List<String> values = allHeaders.get(name);

        if (values == null) {
            values = new ArrayList<String>();
            allHeaders.put(name, values);
        }

        values.add(value);
    }
Adds an HTTP header to the set associated with this response.

@param name
           The name of the HTTP header.
@param value
           The value of the HTTP header.
aws-java-sdk-core/src/main/java/com/amazonaws/http/HttpResponse.java