code: private void handleNoMatch(final HttpServerExchange exchange) throws Exception {
          // if invalidMethodHandler is null we fail fast without matching with allMethodsMatcher
          if (invalidMethodHandler != null && allMethodsMatcher.match(exchange.getRelativePath()) != null) {
              invalidMethodHandler.handleRequest(exchange);
              return;
          }
          fallbackHandler.handleRequest(exchange);
      }
docs: Handles the case in with a match was not found for the http method but might exist for another http method.
  For example: POST not matched for a path but at least one match exists for same path.
  
  @param exchange The object for which its handled the "no match" case.
  @throws Exception