#### Do-stuff-later pool

Sometimes there's an action required like calling the application layer or responding to a ping, and the thread discovering the action is not the thread that should do the work. We enqueue a runnable on this executor and it gets handled by one of the executor's threads.

### Locks

	biggerBufMin = 32 << 10

	// This is the maximum size of bigger buffers.
	biggerBufMax = maxBufferSize

	// If there is a queue, merge up to this many messages.
	maxMergeMessages = 30

	// clientPingInterval will ping the remote handler every 15 seconds.
	// Clients disconnect when we exceed 2 intervals.
	clientPingInterval = 15 * time.Second

	// Deadline for single (non-streaming) requests to complete.

                                  description: The ring/modulo hash load balancer
                                    implements consistent hashing to backend hosts.
                                  properties:
                                    minimumRingSize:
                                      description: The minimum number of virtual nodes
                                        to use for the hash ring.

    when pooled connections are evicted).

    If you have a configured ping interval, you should confirm that it is long
    enough for a roundtrip from client to server. If your ping interval is too
    short, slow connections may be misinterpreted as failed connections. A ping
    interval of 30 seconds is reasonable for most use cases.

pkg database/sql/driver, type NamedValue struct, Ordinal int
pkg database/sql/driver, type NamedValue struct, Value Value
pkg database/sql/driver, type Pinger interface { Ping }
pkg database/sql/driver, type Pinger interface, Ping(context.Context) error
pkg database/sql/driver, type QueryerContext interface { QueryContext }

    )
    val openAtNanos = System.nanoTime()
    newWebSocket()
    clientListener.assertOpen()
    clientListener.assertFailure(
      SocketTimeoutException::class.java,
      "sent ping but didn't receive pong within 500ms (after 0 successful ping/pongs)",
    )
    latch.countDown()
    val elapsedUntilFailure = System.nanoTime() - openAtNanos
    assertThat(TimeUnit.NANOSECONDS.toMillis(elapsedUntilFailure).toDouble())

{"index":{"_index":"fess_config.scheduled_job","_id":"ping_es"}}

                                  description: The ring/modulo hash load balancer
                                    implements consistent hashing to backend hosts.
                                  properties:
                                    minimumRingSize:
                                      description: The minimum number of virtual nodes
                                        to use for the hash ring.

The benefit of raising an exception over `return`ing a value will be more evident in the section about Dependencies and Security.

In this example, when the client requests an item by an ID that doesn't exist, raise an exception with a status code of `404`:

```Python hl_lines="11"

		conn.Close()
		c.handleMsgWg.Done()
	}()

	c.connMu.Lock()
	connPingInterval := c.connPingInterval
	c.connMu.Unlock()
	ping := time.NewTicker(connPingInterval)
	pingFrame := message{
		Op:         OpPing,
		DeadlineMS: 5000,
	}

	defer ping.Stop()
	queue := make([][]byte, 0, maxMergeMessages)
	merged := make([]byte, 0, writeBufferSize)
	var queueSize int
	var buf bytes.Buffer