code: private Map<Method, CheckedFunction1<Object[], Object>> decorateMethodHandlers(Map<Method, MethodHandler> dispatch,
              FeignDecorator invocationDecorator, Target<?> target) {
          final Map<Method, CheckedFunction1<Object[], Object>> map = new HashMap<>();
          for (final Map.Entry<Method, MethodHandler> entry : dispatch.entrySet()) {
              final Method method = entry.getKey();
              final MethodHandler methodHandler = entry.getValue();
              map.put(method, invocationDecorator.decorate(methodHandler::invoke, method, methodHandler, target));
          }
          return map;
      }
docs: Applies the specified {@link FeignDecorator} to all specified {@link MethodHandler}s and
  returns the result as a map of {@link CheckedFunction1}s. Invoking a {@link CheckedFunction1}
  will therefore invoke the decorator which, in turn, may invoke the corresponding
  {@link MethodHandler}.
  
  @param dispatch a map of the methods from the feign interface to the {@link MethodHandler}s.
  @param invocationDecorator the {@link FeignDecorator} with which to decorate the
  {@link MethodHandler}s.
  @param target the target feign interface.
  @return a new map where the {@link MethodHandler}s are decorated with the
  {@link FeignDecorator}.