5.2.0

Added

• Promise signatures for engine.handle (#55)
  • So, in addition to engine.handle(request, callback), you can do e.g. await engine.handle(request).

Changed

• Remove async and promise-to-callback dependencies
  • These dependencies were used internally for middleware flow control.
    They have been replaced with Promises and native async/await, which means that some operations are no longer eagerly executed.
    This change may affect consumers that depend on the eager execution of middleware during request processing, outside of middleware functions and request handlers.
    • In general, it is a bad practice to work with state that depends on middleware execution, while the middleware are executing.