Stop Building Synchronous Web Containers

Seriously, stop it. It's surreally difficult to build a sane ansynchronous service on top of a synchronous API, but building a synchronous service on top of an asynchronous API is easy.

vs

Synchronous web containers are bad API design

Writing synchronous adapters for async APIs is easy

def adapter(request, response_callback):
    synchronous_response = synchronous_entry_point(request)
    return response_callback(synchronous_response)

Going the other way is more or less impossible, which is why websocket support, HTML5 server-sent event support, and every other async tool for the web has an awful server interface.