if ts != nil {
				tot := ts.User + ts.System + ts.Idle + ts.Iowait + ts.Nice + ts.Steal
				cpuUserVal := math.Round(ts.User/tot*100*100) / 100
				updateResourceMetrics(cpuSubsystem, cpuUser, cpuUserVal, labels, false)
				cpuSystemVal := math.Round(ts.System/tot*100*100) / 100
				updateResourceMetrics(cpuSubsystem, cpuSystem, cpuSystemVal, labels, false)
				cpuIdleVal := math.Round(ts.Idle/tot*100*100) / 100

    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.

 * used. HTTP/1.x connections can carry either zero or one streams. HTTP/2 connections can carry any
 * number of streams, dynamically configured with `SETTINGS_MAX_CONCURRENT_STREAMS`. A connection
 * currently carrying zero streams is an idle stream. We keep it alive because reusing an existing
 * connection is typically faster than establishing a new one.
 *
 * When a single logical call requires multiple streams due to redirects or authorization

  }

  @Test
  fun idleCallbackInvokedWhenIdle() {
    val idle = AtomicBoolean()
    dispatcher.idleCallback = Runnable { idle.set(true) }
    client.newCall(newRequest("http://a/1")).enqueue(callback)
    client.newCall(newRequest("http://a/2")).enqueue(callback)
    executor.finishJob("http://a/1")
    assertThat(idle.get()).isFalse()
    val ready = CountDownLatch(1)
    val proceed = CountDownLatch(1)

        this.connectionCheckInterval = connectionCheckInterval;
    }

    /**
     * Sets the idle connection timeout in milliseconds.
     *
     * @param idleConnectionTimeout The idle connection timeout
     */
    public void setIdleConnectionTimeout(final long idleConnectionTimeout) {
        this.idleConnectionTimeout = idleConnectionTimeout;
    }

## Version 2.7.0

_2015-12-13_

 *  **Rewritten connection management.** Previously OkHttp's connection pool
    managed both idle and active connections for HTTP/2, but only idle
    connections for HTTP/1.x. With this update the connection pool manages both
    idle and active connections for everything. OkHttp now detects and warns on
    connections that were allocated but never released, and will enforce HTTP/2

	// 	if trhttp2 != nil {
	// 		// ReadIdleTimeout is the timeout after which a health check using ping
	// 		// frame will be carried out if no frame is received on the
	// 		// connection. 5 minutes is sufficient time for any idle connection.
	// 		trhttp2.ReadIdleTimeout = 5 * time.Minute
	// 		// PingTimeout is the timeout after which the connection will be closed
	// 		// if a response to Ping is not received.
	// 		trhttp2.PingTimeout = dialTimeout

		Usage:  "shutdown timeout to gracefully shutdown server (DEPRECATED)",
		EnvVar: "MINIO_SHUTDOWN_TIMEOUT",
		Hidden: true,
	},

	cli.DurationFlag{
		Name:   "idle-timeout",
		Value:  xhttp.DefaultIdleTimeout,
		Usage:  "idle timeout is the maximum amount of time to wait for the next request when keep-alive are enabled",
		EnvVar: "MINIO_IDLE_TIMEOUT",
		Hidden: true,
	},
	cli.DurationFlag{

        this.connectionCheckInterval = connectionCheckInterval;
    }

    /**
     * Sets the idle connection timeout in milliseconds.
     *
     * @param idleConnectionTimeout The idle connection timeout
     */
    public void setIdleConnectionTimeout(final long idleConnectionTimeout) {
        this.idleConnectionTimeout = idleConnectionTimeout;
    }

Blocking APIs may be inefficient because you hold a thread idle while waiting on the network. Threads are expensive because they have both a memory overhead and a context-switching overhead.

#### Framed protocols