How can you stop a goroutine after a specified time if the result has not been received?

In Go, to stop a goroutine after a specified timeout, you typically use select with a timer or a context with timeout.

Example with time.After:

select {
case result := <-ch:
    // handle result
case <-time.After(2 * time.Second):
    // timeout - no result received within 2 seconds
}

Example with context:

ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
defer cancel()

select {
case result := <-ch:
    // handle result
case <-ctx.Done():
    // timeout or cancellation
}

Thus, if the result does not arrive in time, execution can be canceled and timeout handled.