grpc-gevent error under flask-socketio

Pipfile

[[source]]
name = "pypi"
url = "https://pypi.org/simple"
verify_ssl = true

[dev-packages]

[packages]
gevent = "*"
Flask-SocketIO = "*"
google-cloud-firestore = "*"

[requires]
python_version = "3.5"

run.py

from flask import Flask, jsonify
from flask_socketio import SocketIO
from google.cloud import firestore

app = Flask(__name__)

socketio = SocketIO(app)

db = firestore.Client()


@app.route('/')
def get_():
    return jsonify(list(el.to_dict() for el in db.collection('connections').stream()))


if __name__ == '__main__':
    socketio.run(app, use_reloader=True, debug=True)

test

matthieu@zurkus:~/repro-grpc-gevent$ http get http://localhost:5000/
HTTP/1.1 200 OK
Content-Length: 9
Content-Type: application/json
Date: Tue, 05 Nov 2019 19:54:48 GMT

[
    {}
]

matthieu@zurkus:~/repro-grpc-gevent$ http get http://localhost:5000/
=> hangs forever