if err != nil {
				log.Fatalf("Error reading session policy file: %v", err)
			}
			policy = string(bs)
		}
		stsOpts.Policy = policy
	}
	if expiryDuration != 0 {
		stsOpts.DurationSeconds = int(expiryDuration.Seconds())
	}
	li, err := cr.NewSTSAssumeRole(stsEndpoint, stsOpts)
	if err != nil {
		log.Fatalf("Error initializing STS Identity: %v", err)
	}

	stsEndpointURL, err := url.Parse(stsEndpoint)
	if err != nil {

		avg = l.rttMsSum / float64(l.successRequestCount)
	}
	now := time.Now().UTC()
	return Metrics{
		LastReachableSecs:   now.Sub(o.serviceMetrics.LastCheckSuccess).Seconds(),
		LastUnreachableSecs: now.Sub(o.serviceMetrics.LastCheckFailure).Seconds(),
		TotalRequests:       l.failedRequestCount + l.successRequestCount,
		FailedRequests:      l.failedRequestCount,
		AvgSuccRTTMs:        avg,
		MaxSuccRTTMs:        l.maxRttMs,

* `datetime.timedelta`:
    * A Python `datetime.timedelta`.
    * In requests and responses will be represented as a `float` of total seconds.
    * Pydantic also allows representing it as a "ISO 8601 time diff encoding", <a href="https://docs.pydantic.dev/latest/concepts/serialization/#custom-serializers" class="external-link" target="_blank">see the docs for more info</a>.

  }

  private fun drainCancelQueue(eventSource: EventSource) {
    if (cancel) {
      cancel = false
      eventSource.cancel()
    }
  }

  private fun nextEvent(): Any =
    events.poll(10, TimeUnit.SECONDS)
      ?: throw AssertionError("Timed out waiting for event.")

  fun assertExhausted() {
    assertThat(events).isEmpty()
  }

  fun assertEvent(
    id: String?,
    type: String?,
    data: String,

import static com.google.common.cache.TestingCacheLoaders.identityLoader;
import static com.google.common.truth.Truth.assertThat;
import static java.util.concurrent.TimeUnit.SECONDS;

import com.google.common.cache.LocalCache.LocalLoadingCache;
import com.google.common.cache.LocalCache.Segment;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;

And also after the `response` is generated, before returning it.

For example, you could add a custom header `X-Process-Time` containing the time in seconds that it took to process the request and generate a response:

{* ../../docs_src/middleware/tutorial001_py39.py hl[10,12:13] *}

/// tip

| user               | string                                  | Identifier for owner of requested credentials          |
| maxValiditySeconds | integer (>= 900 seconds and < 365 days) | Maximum allowed expiry duration for the credentials    |
| claims             | key-value pairs                         | Claims to be associated with the requested credentials |

import static java.util.concurrent.Executors.newCachedThreadPool;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.NANOSECONDS;
import static java.util.concurrent.TimeUnit.SECONDS;
import static org.junit.Assert.assertThrows;

import com.google.common.base.Stopwatch;
import java.time.Duration;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

    long cacheByteCount = 1024L * 1024L * 100L;

    Cache cache = new Cache(new File(args[0]), cacheByteCount);
    OkHttpClient client = new OkHttpClient.Builder()
        .cache(cache)
        .callTimeout(5, TimeUnit.SECONDS)
        .build();

    Crawler crawler = new Crawler(client, queueLimit, hostLimit);
    crawler.queue.add(HttpUrl.get(args[1]));
    crawler.parallelDrainQueue(threadCount);
  }

		memCache:          "Cache memory on the node",
		memAvailable:      "Available memory on the node",
		readsPerSec:       "Reads per second on a drive",
		writesPerSec:      "Writes per second on a drive",
		readsKBPerSec:     "Kilobytes read per second on a drive",
		writesKBPerSec:    "Kilobytes written per second on a drive",
		readsAwait:        "Average time for read requests to be served on a drive",