*  Fix: Don't crash with a `NullPointerException` if a server sends a close while we're sending a
    ping. OkHttp had a race condition bug.


## Version 4.6.0

_2020-04-28_

 *  Fix: Follow HTTP 307 and 308 redirects on methods other than GET and POST. We're reluctant to
    change OkHttp's behavior in handling common HTTP status codes, but this fix is overdue! The new

        .build()
    assertFailsWith<IOException> {
      client.newCall(Request.Builder().url(server.url("/0")).build()).execute()
    }.also { expected ->
      assertThat(expected.message).isEqualTo("Too many follow-up requests: 21")
    }
  }

  /**
   * We had a bug where we were passing a null route to the authenticator.
   * https://github.com/square/okhttp/issues/3809
   */
  @Test

          closeActiveExchange = false
          return response
        }

        response.body.closeQuietly()

        if (++followUpCount > MAX_FOLLOW_UPS) {
          throw ProtocolException("Too many follow-up requests: $followUpCount")
        }

        request = followUp
        priorResponse = response
      } finally {
        call.exitNetworkInterceptorExchange(closeActiveExchange)

          ConnectResult(this, nextPlan = connectTcpNextPlan, throwable = IOException("canceled"))
        }
        connectTcpNextPlan != null -> {
          events += "plan $id needs follow-up"
          ConnectResult(this, nextPlan = connectTcpNextPlan)
        }
        else -> {
          events += "plan $id TCP connected"
          connectState = ConnectState.TCP_CONNECTED

     */
    fun authenticator(authenticator: Authenticator) =
      apply {
        this.authenticator = authenticator
      }

    /** Configure this client to follow redirects. If unset, redirects will be followed. */
    fun followRedirects(followRedirects: Boolean) =
      apply {
        this.followRedirects = followRedirects
      }

    /**

   *
   * We get plan0 and plan1 from the route planner.
   * We get plan2 as a follow-up to plan1, typically retry the same IP but different TLS.
   * We get plan3 as a retry of plan0, which was canceled when it lost the race.
   *
   * This test confirms that we prefer to do the TLS follow-up (plan2) before the TCP retry (plan3).
   * It also confirms we enforce the 250 ms delay in each race.
   */
  @Test