$ adb shell setprop log.tag.okhttp.TaskRunner DEBUG
$ adb logcat '*:E' 'okhttp.Http2:D' 'okhttp.TaskRunner:D'
```

### HTTP/2 Frame Logging

This logs inbound (`<<`) and outbound (`>>`) frames for HTTP/2 connections.

```
[2020-01-01 00:00:00] >> CONNECTION 505249202a20485454502f322e300d0a0d0a534d0d0a0d0a
[2020-01-01 00:00:00] >> 0x00000000     6 SETTINGS
[2020-01-01 00:00:00] >> 0x00000000     4 WINDOW_UPDATE

    FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Xmn${FESS_HEAP_NEWSIZE}"
fi

# set to headless, just in case
FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Djava.awt.headless=true"

# maximum # keep-alive connections to maintain at once
FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Dhttp.maxConnections=20"

# Force the JVM to use IPv4 stack
if [ "x$FESS_USE_IPV4" != "x" ]; then
  FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Djava.net.preferIPv4Stack=true"

) {
  /**
   * An obsolete plaintext framing that does not use persistent sockets by default.
   */
  HTTP_1_0("http/1.0"),

  /**
   * A plaintext framing that includes persistent connections.
   *
   * This version of OkHttp implements [RFC 7230][rfc_7230], and tracks revisions to that spec.
   *
   * [rfc_7230]: https://tools.ietf.org/html/rfc7230
   */
  HTTP_1_1("http/1.1"),

  /**

 * Fix bug in HTTP/2 where our HPACK decoder wasn't emitting entries in
   certain eviction scenarios, leading to dropped response headers.

## Version 1.5.1

_2014-03-11_

 * Fix 1.5.0 regression where connections should not have been recycled.
 * Fix 1.5.0 regression where transparent Gzip was broken by attempting to
   recover from another I/O failure.
 * Fix problems where spdy/3.1 headers may not have been compressed properly.

   */
  fun cancel()

  /**
   * Carries an exchange. This is usually a connection, but it could also be a connect plan for
   * CONNECT tunnels. Note that CONNECT tunnels are significantly less capable than connections.
   */
  interface Carrier {
    val route: Route

    fun trackFailure(
      call: RealCall,
      e: IOException?,
    )

    fun noNewExchanges()

    fun cancel()
  }

    clientListener.assertTextMessage("Hello, WebSockets!")
    closeWebSockets(webSocket, server)
  }

  /**
   * We had a bug where web socket connections were leaked if the HTTP connection upgrade was not
   * successful. This test confirms that connections are released back to the connection pool!
   * https://github.com/square/okhttp/issues/4258
   */
  @Test
  @Throws(Exception::class)

   *
   * The deadline to respond to this ping attempts to limit the cost of being wrong. If it is too
   * long, streams created while we await the pong will reuse broken connections and inevitably
   * fail. If it is too short, slow connections will be marked as failed and extra TCP and TLS
   * handshakes will be required.
   *
   * The deadline is currently hardcoded. We may make this configurable in the future!
   */

  ).int()
    .default(DEFAULT_TIMEOUT)

  val followRedirects: Boolean by option("-L", "--location").help("Follow redirects").flag()

  val allowInsecure: Boolean by option("-k", "--insecure").help("Allow connections to SSL sites without certs").flag()

  val showHeaders: Boolean by option("-i", "--include").help("Include protocol headers in the output").flag()

package okhttp3

import java.net.InetAddress
import java.net.InetSocketAddress
import java.net.Socket
import java.net.SocketAddress
import okhttp3.internal.platform.Platform

/**
 * A [SocketFactory] that redirects connections to [defaultAddress] or specific overridden address via [set].
 */
class SpecificHostSocketFactory(
  val defaultAddress: InetSocketAddress?,
) : DelegatingSocketFactory(getDefault()) {

   *
   * If more than [maxRequestsPerHost] requests are in flight when this is invoked, those requests
   * will remain in flight.
   *
   * WebSocket connections to hosts **do not** count against this limit.
   */
  @get:Synchronized
  var maxRequestsPerHost = 5
    set(maxRequestsPerHost) {
      require(maxRequestsPerHost >= 1) { "max < 1: $maxRequestsPerHost" }