Algorithm

lamport clock

The Lamport timestamp algorithm is a simple logical clock algorithm used to determine the order of events in a distributed computer system.

a process increments its counter before each local event
when a process sends a message, it includes its counter value with the message after executing step 1
on receiving a message, the couner of the recipient is updated, if necessary, to the greater of its current counter and the timestamp in the received message. The counter is then incremented by 1 before the message is considered received.

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class LamportClock:
    def __init__(self):
        self.time = 0

    def increment(self):
        """Increment the clock by 1 for local events."""
        self.time += 1

    def send_event(self):
        """Increment the clock for a send event."""
        self.increment()
        return self.time

    def receive_event(self, received_time):
        """Adjust the clock based on the received time from another process."""
        self.time = max(self.time, received_time) + 1

    def __str__(self):
        return str(self.time)

references

https://en.wikipedia.org/wiki/Lamport_timestamp