### Events with Retries and Follow-Ups

OkHttp is resilient and can automatically recover from some connectivity failures. In this case, the `connectFailed()` event is not terminal and not followed by `callFailed()`. Event listeners will receive multiple events of the same type when retries are attempted.

    }
    serverWriter.writeMessageFrame(OPCODE_BINARY, payload.snapshot())

    // Write directly to the unbuffered sink. This ensures it will become single frame.
    assertData("827e") // 'e' == 4-byte follow-up length.
    assertData(format("%04X", payload.completeSegmentByteCount()))
    assertData(payload.readByteString())
  }

  @Test fun serverMessageLengthLong() {

   * OkHttp in the current runtime. Use this to include the OkHttp version in custom `User-Agent`
   * headers.
   *
   * Official OkHttp releases follow [semantic versioning][semver]. Versions with the `-SNAPSHOT`
   * qualifier are not unique and should only be used in development environments. If you create

    help = "Maximum time allowed for the entire call (seconds)",
  ).int().default(DEFAULT_TIMEOUT)

  val followRedirects: Boolean by option("-L", "--location", help = "Follow redirects").flag()

  val allowInsecure: Boolean by option("-k", "--insecure", help = "Allow connections to SSL sites without certs").flag()

  val showHeaders: Boolean by option("-i", "--include", help = "Include protocol headers in the output").flag()

    the certificate that follows and the last certificate is signed by a trusted root.

 *  Fix: Don't lose HTTP/2 flow control bytes when incoming data races with a stream close. If this
    happened enough then eventually the connection would stall.

 *  Fix: Acknowledge and apply inbound HTTP/2 settings atomically. Previously we had a race where we

 *         .build();
 *   }
 * }
 * return null; // Didn't find a preemptive auth scheme.
 * ```
 *
 * ## Reactive Authentication
 *
 * Implementations authenticate by returning a follow-up request that includes an authorization
 * header, or they may decline the challenge by returning null. In this case the unauthenticated
 * response will be returned to the caller that triggered it.
 *

      )

    call.execute().use { response ->
      assertThat(response.body.string()).isEqualTo("abc")
      assertThat(response.trailers()).isEqualTo(headersOf("caboose", "xyz"))
    }
  }

  @Disabled("Follow up with fix in https://github.com/square/okhttp/issues/6853")
  @Test
  fun serverDisconnectsBeforeSecondRequestHttp1() {
    enableProtocol(Protocol.HTTP_1_1)

    server.enqueue(MockResponse(code = 200, body = "Req1"))

    )

    // No authorization header for the first request...
    var request = server.takeRequest()
    assertThat(request.headers["Authorization"]).isNull()

    // ...but the three requests that follow include an authorization header.
    for (i in 0..2) {
      request = server.takeRequest()
      assertThat(request.requestLine).isEqualTo("POST / HTTP/1.1")
      assertThat(request.headers["Authorization"]).isEqualTo(

can make. We therefore encourage reporting security issues with the code
contained in this repository.

If you believe you have discovered a security vulnerability, please follow the
guidelines at https://bugcrowd.com/squareopensource


## Verifying Artifacts

We sign our artifacts using this [key][signing_key]:

```

      requestBody.close()
      assertThat(responseBody.readUtf8Line()).isNull()
    }
    body.awaitSuccess()
  }

  /**
   * Duplex calls that have follow-ups are weird. By the time we know there's a follow-up we've
   * already split off another thread to stream the request body. Because we permit at most one
   * exchange at a time we break the request stream out from under that writer.
   */
  @Test