I am trying to implement the following:

from multiprocessing import Pool
from flask import Flask, jsonify
from flask_cors import CORS
from flask_socketio import SocketIO, send, emit

app = Flask(__name__)

CORS(app)
socketio = SocketIO(app, cors_allowed_origins="*")



@socketio.on('connect')
def connect():
    emit('result', {'data': 'Connected'})


def ab_test(data):
    socketio.emit('result', {'data': data})
    return "OK"


@app.route('/api/test', methods=['POST'])
def test():
    users = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]
    with Pool(2) as p:
        data_pool = users
        result = p.map(ab_test, data_pool)
    return jsonify({"status": "complete"})



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

Please explain to me why when using Pool my messages are not sent to the Client via socket?

For example , if you do this , then everything works:

def ab_test(data):
    socketio.emit('result', {'data': data})
    return "OK"


@app.route('/api/test', methods=['POST'])
def test():
    users = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]
    for user in users:
        ab_test(user)
    return jsonify({"status": "complete"})