OkHttpClient client1 = client.newBuilder()
        .readTimeout(500, TimeUnit.MILLISECONDS)
        .build();
    try (Response response = client1.newCall(request).execute()) {
      System.out.println("Response 1 succeeded: " + response);
    } catch (IOException e) {
      System.out.println("Response 1 failed: " + e);
    }

    // Copy to customize OkHttp for this request.
    OkHttpClient client2 = client.newBuilder()

      "s/version = \".*\"/version = \"$NEXT_VERSION\"/g" \
      build.gradle.kts
    git commit -am "Prepare next development version."
    git push
    ```

7. Confirm the [GitHub Actions][github_actions] publish job succeeded.

[github_actions]: https://github.com/square/okhttp/actions

must block on writing I/O. We can't return from a write until we've pushed its bytes onto the socket. Otherwise, if the write fails we are unable to deliver its IOException to the application. We would have told the application layer that the write succeeded, but it didn't!

The application-layer can also do blocking reads. If the application asks to read and there's nothing available, we need to hold that thread until either the bytes arrive, the stream is closed, or a timeout elapses. If we...

          throw ProtocolException("unexpected address: " + toSocket.localAddress)
        }

        // Write the reply.
        fromSink.writeByte(VERSION_5)
        fromSink.writeByte(REPLY_SUCCEEDED)
        fromSink.writeByte(0)
        fromSink.writeByte(ADDRESS_TYPE_IPV4)
        fromSink.write(localAddress)
        fromSink.writeShort(toSocket.localPort)
        fromSink.emit()

   */
  fun cancel()

  fun interface Factory {
    /**
     * Creates a new event source and immediately returns it. Creating an event source initiates an
     * asynchronous process to connect the socket. Once that succeeds or fails, `listener` will be
     * notified. The caller must cancel the returned event source when it is no longer in use.
     */
    fun newEventSource(
      request: Request,
      listener: EventSourceListener,

    val inputStream = response.body.byteStream()
    assertThat(inputStream.read().toChar()).isEqualTo('A')
    call.cancel()
    assertFailsWith<IOException> {
      // Reading 'B' may succeed if it's buffered.
      inputStream.read()

      // But 'C' shouldn't be buffered (the response is throttled) and this should fail.
      inputStream.read()
    }
    inputStream.close()
  }

    val client1 =
      client.newBuilder()
        .readTimeout(500, TimeUnit.MILLISECONDS)
        .build()
    try {
      client1.newCall(request).execute().use { response ->
        println("Response 1 succeeded: $response")
      }
    } catch (e: IOException) {
      println("Response 1 failed: $e")
    }

    // Copy to customize OkHttp for this request.
    val client2 =
      client.newBuilder()

            buffer.write(byteBuffer)
            byteBuffer.clear()
            request.read(byteBuffer)
          }

          override fun onSucceeded(
            request: UrlRequest,
            info: UrlResponseInfo,
          ) {
            println("onSucceeded ${info.headers.asMap}")
            completableFuture.complete(Response(info.httpStatusCode, info.negotiatedProtocol, buffer.readUtf8()))
          }

 *  * Preemptive proxy authentication failed.
 *
 * Planning failures are not necessarily fatal. For example, even if we can't DNS lookup the first
 * proxy in a list, looking up a subsequent one may succeed.
 */
internal class FailedPlan(e: Throwable) : RoutePlanner.Plan {
  val result = RoutePlanner.ConnectResult(plan = this, throwable = e)

  override val isReady = false

  override fun connectTcp() = result

import okhttp3.internal.okHttpName

/**
 * Speculatively connects to each IP address of a target address, returning as soon as one of them
 * connects successfully. This kicks off new attempts every 250 ms until a connect succeeds.
 */
internal class FastFallbackExchangeFinder(
  override val routePlanner: RoutePlanner,
  private val taskRunner: TaskRunner,
) : ExchangeFinder {
  private val connectDelayNanos = TimeUnit.MILLISECONDS.toNanos(250L)