private String getHeaderCaseInsensitive(String name) {
            Validate.notNull(name, "Header name must not be null");
            // quick evals for common case of title case, lower case, then scan for mixed
            String value = headers.get(name);
            if (value == null)
                value = headers.get(name.toLowerCase());
            if (value == null) {
                Map.Entry<String, String> entry = scanHeaders(name);
                if (entry != null)
                    value = entry.getValue();
            }
            return value;
        }