private fun List<String?>.toQueryString(out: StringBuilder) {
      for (i in 0 until size step 2) {
        val name = this[i]
        val value = this[i + 1]
        if (i > 0) out.append('&')
        out.append(name)
        if (value != null) {
          out.append('=')
          out.append(value)
        }
      }
    }

    /**

    regression that was introduced in OkHttp 3.14.5.


## Version 3.14.5

_2020-01-03_

 *  Fix: Degrade HTTP/2 connections after a timeout. When an HTTP/2 stream times out it may impact
    the stream only or the entire connection. With this fix OkHttp will now send HTTP/2 pings after
    a stream timeout to determine whether the connection should remain eligible for pooling.


## Version 3.14.4

        .build()

    // Stalling the socket will cause TWO requests to time out!
    server.enqueue(MockResponse(socketPolicy = StallSocketAtStart))

    // The 3rd request should be sent to a fresh connection.
    server.enqueue(
      MockResponse(body = "fresh connection"),
    )

    // The first call times out.
    val call1 = client.newCall(Request(server.url("/")))
    assertFailsWith<IOException> {

      this.certificatePinner =
        builder.certificatePinner
          .withCertificateChainCleaner(certificateChainCleaner!!)
    }

    verifyClientState()
  }

  /**
   * Creates an [Address] of out of the provided [HttpUrl]
   * that uses this client’s DNS, TLS, and proxy configuration.
   */
  fun address(url: HttpUrl): Address {
    var useSslSocketFactory: SSLSocketFactory? = null

          .url(server.url("/"))
          .build(),
      )
    assertFailsWith<IOException> {
      call.execute()
    }.also { expected ->
      assertThat(expected.message).isIn("timeout", "Read timed out")
    }
    assertThat(listener.recordedEventTypes()).containsExactly(
      "CallStart",
      "ProxySelectStart", "ProxySelectEnd", "DnsStart", "DnsEnd",

    peer.play()

    // Play it back.
    val connection = connect(peer)
    val client = connection.newStream(headerEntries("b", "banana"), true)
    val out = client.getSink().buffer()
    out.write(EMPTY_BYTE_ARRAY)
    out.flush()
    out.close()

    // Verify the peer received what was expected.
    assertThat(peer.takeFrame().type).isEqualTo(Http2.TYPE_HEADERS)