* `INADEQUATE_SECURITY`.
   */
  HTTP_2("h2"),

  /**
   * Cleartext HTTP/2 with no "upgrade" round trip. This option requires the client to have prior
   * knowledge that the server supports cleartext HTTP/2.
   *
   * See also [Starting HTTP/2 with Prior Knowledge][rfc_7540_34].
   *
   * [rfc_7540_34]: https://tools.ietf.org/html/rfc7540.section-3.4
   */
  H2_PRIOR_KNOWLEDGE("h2_prior_knowledge"),

  /**

import okhttp3.RequestBody
import okhttp3.SimpleProvider
import okhttp3.internal.http.CancelTest.CancelMode.CANCEL
import okhttp3.internal.http.CancelTest.CancelMode.INTERRUPT
import okhttp3.internal.http.CancelTest.ConnectionType.H2
import okhttp3.internal.http.CancelTest.ConnectionType.HTTP
import okhttp3.internal.http.CancelTest.ConnectionType.HTTPS
import okhttp3.testing.PlatformRule
import okio.Buffer
import okio.BufferedSink

      // Treating this use case as user error
      server.protocols = listOf(Protocol.H2_PRIOR_KNOWLEDGE, Protocol.H2_PRIOR_KNOWLEDGE)
      fail<Unit>()
    } catch (expected: IllegalArgumentException) {
      assertThat(expected.message).isEqualTo(
        "protocols containing h2_prior_knowledge cannot use other protocols: " +
          "[h2_prior_knowledge, h2_prior_knowledge]",
      )
    }
  }

  @Test

      // Treating this use case as user error
      server.protocols = listOf(Protocol.H2_PRIOR_KNOWLEDGE, Protocol.H2_PRIOR_KNOWLEDGE)
      fail<Any>()
    } catch (expected: IllegalArgumentException) {
      assertThat(expected.message).isEqualTo(
        "protocols containing h2_prior_knowledge cannot use other protocols: " +
          "[h2_prior_knowledge, h2_prior_knowledge]",
      )
    }
  }

  @Test

  private val http2Connection: Http2Connection,
) : ExchangeCodec {
  @Volatile private var stream: Http2Stream? = null

  private val protocol: Protocol =
    if (Protocol.H2_PRIOR_KNOWLEDGE in client.protocols) {
      Protocol.H2_PRIOR_KNOWLEDGE
    } else {
      Protocol.HTTP_2
    }

  @Volatile
  private var canceled = false

  override fun createRequestBody(
    request: Request,

    server.setProtocols(Collections.singletonList(Protocol.H2_PRIOR_KNOWLEDGE));
    server.enqueue(new MockResponse().setBody("hello"));
    server.start();

    OkHttpClient client = new OkHttpClient.Builder()
        .socketFactory(new UnixDomainSocketFactory(socketFile))
        .protocols(Collections.singletonList(Protocol.H2_PRIOR_KNOWLEDGE))
        .build();

    Request request = new Request.Builder()

```
$ adb logcat '*:E' OkHttp:D Http2:D TestRunner:D TaskRunner:D OkHttpTest:D GnssHAL_GnssInterface:F DeviceStateChecker:F memtrack:F
...
01-01 12:53:32.811 10999 11089 D OkHttp  : [49 ms] responseHeadersEnd: Response{protocol=h2, code=200, message=, url=https://1.1.1.1/dns-query?dns=AAABAAABAAAAAAAAA3d3dwhmYWNlYm9vawNjb20AABwAAQ}
01-01 12:53:32.811 10999 11089 D OkHttp  : [49 ms] responseBodyStart

    assertThat(get("http/1.1")).isEqualTo(Protocol.HTTP_1_1)
    assertThat(get("spdy/3.1")).isEqualTo(Protocol.SPDY_3)
    assertThat(get("h2")).isEqualTo(Protocol.HTTP_2)
    assertThat(get("h2_prior_knowledge")).isEqualTo(Protocol.H2_PRIOR_KNOWLEDGE)
    assertThat(get("quic")).isEqualTo(Protocol.QUIC)
    assertThat(get("h3")).isEqualTo(Protocol.HTTP_3)
    assertThat(get("h3-29")).isEqualTo(Protocol.HTTP_3)
  }

    this.withLock {
      successCount++
    }
  }

  @Throws(IOException::class)
  fun start() {
    idleAtNs = System.nanoTime()
    if (protocol == Protocol.HTTP_2 || protocol == Protocol.H2_PRIOR_KNOWLEDGE) {
      startHttp2()
    }
  }

  @Throws(IOException::class)
  private fun startHttp2() {
    val socket = this.socket!!
    val source = this.source!!
    val sink = this.sink!!

    font-weight: 700;
    font-style: normal
}

body, input {
    font-family: cash-market,"Helvetica Neue",helvetica,sans-serif;
}

.md-typeset h1, .md-typeset h2, .md-typeset h3, .md-typeset h4 {
    font-family: cash-market,"Helvetica Neue",helvetica,sans-serif;
    line-height: normal;
    font-weight: bold;
}

button.dl {
  font-weight: 300;
  font-size: 25px;