How to POST the refresh token to Flask JWT Extended?

I am trying to refresh a JWT token from the code here. The issue is with how to get the new token with the refresh.

This works:

curl http://127.0.0.1:5000/protected
{"msg":"Missing Authorization Header"}

This works and I get my token and put it in ACCESS

curl -H "Content-Type: application/json" -X POST   -d '{"username":"test","password":"test"}' http://localhost:5000/login

This works and I get my username

curl -H "Authorization: Bearer $ACCESS" http://localhost:5000/protected

But when the token expires, how do I get curl with my refresh token and/or access token to get my new access token? I've tried numerous POST's and nothing seems to work:

https://flask-jwt-extended.readthedocs.io/en/latest/refresh_tokens.html

from flask import Flask, jsonify, request
from flask_jwt_extended import (
    JWTManager, jwt_required, create_access_token,
    jwt_refresh_token_required, create_refresh_token,
    get_jwt_identity
)

app = Flask(__name__)

app.config['JWT_SECRET_KEY'] = 'super-secret'  # Change this!
jwt = JWTManager(app)


@app.route('/login', methods=['POST'])
def login():
    username = request.json.get('username', None)
    password = request.json.get('password', None)
    if username != 'test' or password != 'test':
        return jsonify({"msg": "Bad username or password"}), 401

    # Use create_access_token() and create_refresh_token() to create our
    # access and refresh tokens
    ret = {
        'access_token': create_access_token(identity=username),
        'refresh_token': create_refresh_token(identity=username)
    }
    return jsonify(ret), 200


# The jwt_refresh_token_required decorator insures a valid refresh
# token is present in the request before calling this endpoint. We
# can use the get_jwt_identity() function to get the identity of
# the refresh token, and use the create_access_token() function again
# to make a new access token for this identity.
@app.route('/refresh', methods=['POST'])
@jwt_refresh_token_required
def refresh():
    current_user = get_jwt_identity()
    ret = {
        'access_token': create_access_token(identity=current_user)
    }
    return jsonify(ret), 200


@app.route('/protected', methods=['GET'])
@jwt_required
def protected():
    username = get_jwt_identity()
    return jsonify(logged_in_as=username), 200


if __name__ == '__main__':
    app.run()

Try

curl -H "Authorization: Bearer $REFRESH" -X POST http://localhost:5000/refresh