Feature Request: allow dispatch to take a Callable which generates the payload

[judahrand]

Sometimes generating the payload of an event might involve some serialization overhead which would be better deferred until after the response has been sent. An example of this might be converting a numpy array to a type which is compatible with json.dumps.

I'm imagining something like:

@app.route("/")
async def root(request: Request) -> JSONResponse:
    arr = np.random.random(512)
    dispatch("new event", payload=lambda: {'arr': arr.tolist()})
    return JSONResponse()