code: public List<String> getHeader(String name) {
          if (headers == null) {
              return null;
          }
          return headers.values(name);
      }
docs: Get the header values for the given header name, if it exists. There can be more than one value
  for a given header name.
  
  @param name the name of the header to get
  @return the values of the given header name