true
          } catch (e: Exception) {
            false
          }
        }
        .build()

    val request =
      Request.Builder()
        .url("https://sni.cloudflaressl.com/cdn-cgi/trace")
        .header("Host", "cloudflare-dns.com")
        .build()
    client.newCall(request).execute().use { response ->
      assertThat(response.code).isEqualTo(200)

    printEvent("callStart");
  }

  @Override public void callEnd(Call call) {
    printEvent("callEnd");
  }

  ...
}
```

We can use this listener to race a pair of concurrent HTTP requests:

```java
Request washingtonPostRequest = new Request.Builder()
    .url("https://www.washingtonpost.com/")
    .build();

          }
        }

        val nextPlan = connectResult.nextPlan
        if (nextPlan != null) {
          // Try this plan's successor before deferred plans because it won the race!
          routePlanner.deferredPlans.addFirst(nextPlan)
        }
      }
    } finally {
      cancelInFlightConnects()
    }

    throw firstException!!
  }

  /**

 * Don't start a new attempt until 250 ms after the most recent attempt was started.
 * Keep whichever TCP connection succeeds first and cancel all the others.
 * Race TCP only. Only attempt a TLS handshake on the winning TCP connection.

our best to right the wrong.

Although this list cannot be exhaustive, we explicitly honor diversity in age, culture, ethnicity,
gender identity or expression, language, national origin, political beliefs, profession, race,
religion, sexual orientation, socioeconomic status, and technical ability. We will not tolerate
discrimination based on any of the protected characteristics above, including participants with
disabilities.

Reporting Issues

 * Fix: Ensure `null` is never returned from a connection's `getHeaderFields()`.
 * Fix: Persist proper `Content-Encoding` header to cache for GZip responses.
 * Fix: Eliminate rare race condition in SPDY streams that would prevent connection reuse.
 * Fix: Change HTTP date formats to UTC to conform to RFC2616 section 3.3.
 * Fix: Support SPDY header blocks with trailing bytes.

 *
 *  3. Attempt plans from prior connect attempts for this call. These occur as either follow-ups to
 *     failed connect attempts (such as trying the next [ConnectionSpec]), or as attempts that lost
 *     a race in fast follow-up.
 *
 *  4. If there's no existing connection, make a list of routes (which may require blocking DNS
 *     lookups) and attempt a new connection them. When failures occur, retries iterate the list of