Is it possible to include a forward slash in a route dynamic property? Is it possible to include forward slashes in routing parameters?

// routing.yml
mymodule.route
    path: '/mymodule/{param}'
    defaults:
        path: ''
    requirements
        path: '[A-Za-z0-9\-\/]+'


/mymodule/this/is/a/single/param would then result in

$param = 'this/is/a/single/param';


being passed into the controller method.
I tested this out, and it doesn't work in Drupal 8, unfortunately.

mymodule.test:
  path: '/mymodule/{testparam}'
  defaults:
    _controller: '\Drupal\mymodule\Controller\TestController::build'
    _title: 'Variable Parameter'
  requirements:
    _permission: 'access content'
    testparam: .+


It picks up the route with "/mymodule/hello", but not "/mymodule/hello/world".

There's some more discussion of this here:
Slashes in single route parameter or other ways to handle a menu tail with dynamic number of params

It looks like there's a solution, but it's pretty heavy handed.