code: public String value(String name) {
          final HttpHeader header = getHeader(name);
          return header == null ? null : header.value();
      }
docs: Get the header value for the provided header name. Null will be returned if the header
  name isn't found.
  
  @param name the name of the header to look for
  @return The String value of the header, or null if the header isn't found