lines.append("")
    lines.append("")
    return "\n".join(lines).encode("utf-8")


# Keep-alive comment, per the SSE spec recommendation
KEEPALIVE_COMMENT = b": ping\n\n"

# Seconds between keep-alive pings when a generator is idle.
# Private but importable so tests can monkeypatch it.

                log.debug("Error closing server socket", e);
            }
        }

        if (serverThread != null) {
            try {
                serverThread.join(5000); // Wait up to 5 seconds
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            }
        }

        registrations.clear();
        log.info("Mock witness service stopped");

		avg = l.rttMsSum / float64(l.successRequestCount)
	}
	now := time.Now().UTC()
	return Metrics{
		LastReachableSecs:   now.Sub(o.serviceMetrics.LastCheckSuccess).Seconds(),
		LastUnreachableSecs: now.Sub(o.serviceMetrics.LastCheckFailure).Seconds(),
		TotalRequests:       l.failedRequestCount + l.successRequestCount,
		FailedRequests:      l.failedRequestCount,
		AvgSuccRTTMs:        avg,
		MaxSuccRTTMs:        l.maxRttMs,

import static java.util.concurrent.Executors.newFixedThreadPool;
import static java.util.concurrent.Executors.newScheduledThreadPool;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.SECONDS;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import com.google.common.base.Preconditions;
import com.google.common.base.Stopwatch;

        
        // Schedule periodic health checks
        scheduler.scheduleAtFixedRate(this::performHealthCheck, 10, 10, TimeUnit.SECONDS);
        
        // Schedule interface discovery
        scheduler.scheduleAtFixedRate(this::discoverInterfaces, 0, 30, TimeUnit.SECONDS);
    }
    
    public void initializeMultiChannel() throws IOException {
        // Check server capability

* `expose_headers` - Indicate any response headers that should be made accessible to the browser. Defaults to `[]`.
* `max_age` - Sets a maximum time in seconds for browsers to cache CORS responses. Defaults to `600`.

The middleware responds to two particular types of HTTP request...

### CORS preflight requests { #cors-preflight-requests }

      this.delegate = null
      delegate.onFailure(webSocket, t, response)
    } else {
      events.add(Failure(t, response))
    }
  }

  private fun nextEvent(): Any =
    events.poll(10, TimeUnit.SECONDS)
      ?: throw AssertionError("Timed out waiting for event.")

  fun assertTextMessage(payload: String?) {
    assertThat(nextEvent()).isEqualTo(Message(string = payload))
  }

                }
            });
        }

        // Start all threads
        startLatch.countDown();

        // Wait for completion
        assertTrue(endLatch.await(30, TimeUnit.SECONDS), "All threads should complete");
        executor.shutdown();

        // Then - All operations should succeed
        assertTrue(exceptions.isEmpty(), "No exceptions should occur");

Isso inclui, por exemplo:

* Notificações por e-mail enviadas após realizar uma ação:
    * Como conectar-se a um servidor de e-mail e enviar um e-mail tende a ser “lento” (vários segundos), você pode retornar a resposta imediatamente e enviar a notificação por e-mail em segundo plano.
* Processamento de dados:

* `expose_headers` - Indica quaisquer cabeçalhos de resposta que devem ser disponibilizados ao navegador. O padrão é `[]`.
* `max_age` - Define um tempo máximo em segundos para os navegadores armazenarem em cache as respostas CORS. O padrão é `600`.

O middleware responde a dois tipos específicos de solicitação HTTP...

### Requisições CORS pré-voo (preflight) { #cors-preflight-requests }