src/Zipkin/Recording/Span.php
public function finish(?int $finishTimestamp = null): void
    {
        if ($this->finished) {
            return;
        }

        if ($this->timestamp !== null && $finishTimestamp !== null) {
            $this->duration = $finishTimestamp - $this->timestamp;
        }

        $this->finished = true;
    }
public function finish(?int $finishTimestamp = null): void
    {
        if ($this->finished) {
            return;
        }

        if ($this->timestamp !== null && $finishTimestamp !== null) {
            $this->duration = $finishTimestamp - $this->timestamp;
        }

        $this->finished = true;
    }
Completes and reports the span

@param int|null $finishTimestamp