collector.checkResolveCall(bindingContext.get(BindingContext.LOOP_RANGE_HAS_NEXT_RESOLVED_CALL, expression.loopRange))
                collector.checkResolveCall(bindingContext.get(BindingContext.LOOP_RANGE_NEXT_RESOLVED_CALL, expression.loopRange))
            }

            override fun visitProperty(property: KtProperty) {
                super.visitProperty(property)

    if (!newRouteSelector.hasNext()) throw IOException("exhausted all routes")
    val newRouteSelection = newRouteSelector.next()
    routeSelection = newRouteSelection

    if (isCanceled()) throw IOException("Canceled")

    return planConnectToRoute(newRouteSelection.next(), newRouteSelection.routes)
  }

  /**
   * Returns a plan to reuse a pooled connection, or null if the pool doesn't have a connection for

        continue
      }

      // Search for the certificate in the chain that signed this certificate. This is typically
      // the next element in the chain, but it could be any element.
      val i = queue.iterator()
      while (i.hasNext()) {
        val signingCert = i.next() as X509Certificate
        if (verifySignature(toVerify, signingCert, result.size - 1)) {
          i.remove()
          result.add(signingCert)

6. Prepare for ongoing development and push to GitHub.

    ```
    sed -i "" \
      "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

 * ----------
 *
 * Tasks control their recurrence schedule. The [runOnce] function returns -1L to signify that the
 * task should not be executed again. Otherwise it returns a delay until the next execution.
 *
 * A task has at most one next execution. If the same task instance is scheduled multiple times, the
 * earliest one wins. This applies to both executions scheduled with [TaskRunner.Queue.schedule] and

): List<T> {
  val ia = a.iterator()
  val ib = b.iterator()

  return buildList {
    while (ia.hasNext() || ib.hasNext()) {
      if (ia.hasNext()) {
        add(ia.next())
      }
      if (ib.hasNext()) {
        add(ib.next())
      }
    }
  }
}

// TODO check read only options for creating lists
public fun <T> List<T>.readOnly() = this.toList()

!!! info
    In this example we use invented custom headers `X-Key` and `X-Token`.

    But in real cases, when implementing security, you would get more benefits from using the integrated [Security utilities (the next chapter)](../security/index.md){.internal-link target=_blank}.

## Dependencies errors and return values

You can use the same dependency *functions* you use normally.

### Dependency requirements

But first, let's check some small concepts.

## In a hurry?

If you don't care about any of these terms and you just need to add security with authentication based on username and password *right now*, skip to the next chapters.

## OAuth2

OAuth2 is a specification that defines several ways to handle authentication and authorization.

It is quite an extensive specification and covers several complex use cases.

!!! tip
    The next sections are **not necessarily "advanced"**.

    And it's possible that for your use case, the solution is in one of them.

## Read the Tutorial first

The next sections assume you already read the main [Tutorial - User Guide: Security](../../tutorial/security/index.md){.internal-link target=_blank}.

    assertThat(actualUrls).containsExactly(*expectedUrls)
  }

  fun finishJob(url: String) {
    val i = calls.iterator()
    while (i.hasNext()) {
      val call = i.next()
      if (call.request.url.toString() == url) {
        i.remove()
        dispatcherTest.dispatcher.finishedAccessor(call)
        return
      }
    }
    throw AssertionError("No such job: $url")
  }