stuck on the old version.

 *  **There is no longer a global singleton connection pool.** In OkHttp 2.x,
    all `OkHttpClient` instances shared a common connection pool by default.
    In OkHttp 3.x, each new `OkHttpClient` gets its own private connection pool.
    Applications should avoid creating many connection pools as doing so
    prevents connection reuse. Each connection pool holds its own set of

import java.io.IOException
import java.util.concurrent.TimeUnit
import okhttp3.Call
import okhttp3.Connection
import okhttp3.Interceptor
import okhttp3.Request
import okhttp3.Response
import okhttp3.internal.checkDuration
import okhttp3.internal.connection.Exchange
import okhttp3.internal.connection.RealCall

/**
 * A concrete interceptor chain that carries the entire interceptor chain: all application

  ) {
    logWithTime("connectFailed: $protocol $ioe")
  }

  override fun connectionAcquired(
    call: Call,
    connection: Connection,
  ) {
    logWithTime("connectionAcquired: $connection")
  }

  override fun connectionReleased(
    call: Call,
    connection: Connection,
  ) {
    logWithTime("connectionReleased")
  }

  override fun requestHeadersStart(call: Call) {

 * limitations under the License.
 */
package okhttp3.internal

import okhttp3.Cache
import okhttp3.Dispatcher
import okhttp3.Response
import okhttp3.internal.connection.Exchange
import okhttp3.internal.connection.RealCall
import okhttp3.internal.connection.RealConnection
import okio.FileSystem
import okio.Path

internal fun buildCache(
  file: Path,
  maxSize: Long,
  fileSystem: FileSystem,

    }
  }

  @Test fun headersEquals() {
    val headers1 =
      Headers
        .Builder()
        .add("Connection", "close")
        .add("Transfer-Encoding", "chunked")
        .build()
    val headers2 =
      Headers
        .Builder()
        .add("Connection", "close")
        .add("Transfer-Encoding", "chunked")
        .build()
    assertThat(headers2).isEqualTo(headers1)

        Request
          .Builder()
          .url(server.url("/"))
          .header("Connection", "upgrade")
          .post("Hello".toRequestBody())
          .build()
      }
    assertThat(e).hasMessage("expected a null request body with 'Connection: upgrade'")
  }

  private fun enableTls(vararg protocols: Protocol) {
    client =
      client
        .newBuilder()

            clientTestRule.wrap(
              object : EventListener() {
                override fun connectionAcquired(
                  call: Call,
                  connection: Connection,
                ) {
                  socketClass = connection.socket().javaClass.name
                }
              },
            ),
          ).build()

      val response = client.newCall(request).execute()

    @Throws(IOException::class)
    fun proceed(request: Request): Response

    /**
     * Returns the connection the request will be executed on. This is only available in the chains
     * of network interceptors; for application interceptors this is always null.
     */
    fun connection(): Connection?

    fun call(): Call

    fun connectTimeoutMillis(): Int

    fun withConnectTimeout(
      timeout: Int,

   * HTTP/2 can have both stream timeouts (due to a problem with a single stream) and connection
   * timeouts (due to a problem with the transport). When a stream times out we don't know whether
   * the problem impacts just one stream or the entire connection.
   *
   * To differentiate the two cases we ping the server when a stream times out. If the overall
   * connection is fine the ping will receive a pong; otherwise it won't.
   *

  }

  @Test
  fun staleConnectionNotReusedForNonIdempotentRequest() {
    // Capture the connection so that we can later make it stale.
    var connection: RealConnection? = null
    client =
      client
        .newBuilder()
        .addNetworkInterceptor(
          Interceptor { chain ->
            connection = chain.connection() as RealConnection
            chain.proceed(chain.request())
          },
        ).build()