Zend Expressive, what's up mate?

stuff.php

<?php
// This is all going to be in one file here, but is split to different classes in real world
// Also intentionally left out bits and pieces not required for the sake of the example

$app = new Application($router, $container);

$app->pipe(MyMiddleware::class);

$app->pipeRoutingMiddleware();

$app->pipeDispatchMiddleware();

$app->get('/', HomePage::class);

$app->run();

// Here the middleware is quite alright like this
class HomePage
{
  public function __invoke($request, $delegate)
  {
    // do stuff, create template, return new response
    return new HtmlResponse($template);
  }
}

// If this MyMiddleware doesn't implement Interop\Http\ServerMiddleware\MiddlewareInterface
// then it must look like this:
// Because HomePage returns a response and MyMiddleware doesn't implement the MiddlewareInterface
class MyMiddleware
{
  public function __invoke($request, $response, $delegate)
  {
    // do stuff
  }
}
// And suddenly it **must** follow the stratigility 1.x-like __invoke signature
// But if no middleware down the chain returns a response, MyMiddleware can be like
// public function __invoke($request, $delegate)

// The docs say the new middleware https://zendframework.github.io/zend-expressive/reference/migration/to-v2/#http-interop
// can either have the process($request, $delegate) signature, or, and I quote:
// "Callable middleware that follows the above signature (the typehint for the request argument is optional)"
// where "above signature" refers to the process($request, $delegate) signature

// What does this tell us?
// That the docs lie, and that if a middleware doesn't implement the MiddlewareInterface
// the middlewares higher up the stack (piped first) will be at the mercy of the middlewares lower at the stack (piped last).
// Am I at fault? Maybe.
// But the docs say that my middleware "CAN" implement the MiddlewareInterface, which means they are not required to do so.
// And if they don't, the __invoke signature of those middlewares changes based on is there a response or not.