假设我们在Python中有以下简单的RabbitMQ回调逻辑：

import pika
connection = pika.BlockingConnection(pika.ConnectionParameters('localhost', 5672, '/', pika.PlainCredentials("user", "password")))
channel = connection.channel()
msg_count = 0
def callback(ch, method, properties, body):
    global msg_count
    msg_count += 1
    print("Received %i messages" % msg_count)
channel.basic_consume(queue="my_queue", on_message_callback=callback, auto_ack=True)

如果一个生产者几乎同时发送两条消息，是否有可能由于竞争条件而打印两次“Received 1 messages”？
我只是不确定这些回调是如何运行的--它们是并发运行的吗？在一个线程？其他方法？