Stalled JSON Response

[cancan101]

Wondering if anyone has built a Response that "stalls" a JSON response, by using a streaming HTTP response that writes spaces, etc to the stream, until the full response is ready? The idea here would be to work around limitations in services like Heroku, which expect there to be response data written otherwise they close the connection. A similar proposal was made for Ruby: https://stackoverflow.com/a/38928195/2638485.

One idea would be to modify the StreamingResponse to have something like this: https://github.com/sysid/sse-starlette/blob/2d90414a452f29532a2c2e6fbc78f80563cad651/sse_starlette/sse.py#L239-L240 where a ping task (safely) writes the spaces until the json response is ready.

Curious if that approach makes sense and / or if there are third party libraries that handle this already?