How correct is the behavior of the Stop method when called repeatedly, with the first call waiting and the second immediately returning?

The behavior of the Stop method when called repeatedly, with the first call blocking (waiting for completion) and the second returning immediately, can be correct if it is explicitly documented and aligns with the logic of the system.

Such behavior is often implemented through synchronization mechanisms, for example, using sync.Once or channels, to ensure that the stop operation occurs only once, and subsequent calls do not block or cause errors.

If the first call to Stop waits for the process to finish, and the second call returns immediately, this prevents deadlocks and duplicate stops, improving the robustness and predictability of the code.

It is important that:

• The first call truly completes all necessary operations.
• Subsequent calls do not lead to race conditions or inconsistent states.

An example with sync.Once:

var stopOnce sync.Once

func Stop() {
    stopOnce.Do(func() {
        // stop logic
        time.Sleep(time.Second) // simulate wait
    })
}

In this example, the first call blocks during execution, while subsequent calls return immediately.