The Sanic built-in server blocks for exactly 90 seconds on status code 412

[ekzhang]

Is there an existing issue for this?

• [X] I have searched the existing issues

Describe the bug

Sanic, like most web servers, usually responds to requests. However, if the response has status code 412, it is very slow and takes exactly 90 extra seconds to respond, stalling after the handler finishes.

This behavior does not happen when running Sanic with uvicorn. Only the official Sanic server. It also doesn't happen with FastAPI.

Code snippet

import sanic

app = sanic.Sanic(__name__)

@app.get("/")
async def root(req: sanic.Request):
    status = int(req.args.get("status", "200"))
    return sanic.json({"message": "Hello World"}, status=status)

Expected Behavior

sanic main:app --port 8051

Then:

$ curl http://localhost:8051
{"message":"Hello World"}
$ curl http://localhost:8051/?status=400  # fine
{"message":"Hello World"}
$ curl http://localhost:8051/?status=411  # fine
{"message":"Hello World"}
$ curl http://localhost:8051/?status=413  # fine
{"message":"Hello World"}
$ curl http://localhost:8051/?status=412
# stalls with no response for 90 seconds

How do you run Sanic?

Sanic CLI

Operating System

Linux

Sanic Version

Sanic v23.6.0

Additional context

I have reproduced this on both Linux and macOS. I have also reproduced this using both the Sanic CLI and the Sanic.serve() function programmatically.