code: public static <O> O deserialise(HttpServletRequest request,
                                      Class<O> requestMessageType) throws IOException {
  
          return deserialise(request.getInputStream(), requestMessageType);
      }
docs: Deserialises the given {@link HttpServletRequest} to a JSON String.
  
  @param request            The request to deserialise.
  @param requestMessageType The message type to deserialise into.
  @param <O>                The type to deserialise to.
  @return A new instance of the given type.
  @throws IOException If an error occurs in reading from the request input stream.