*
   * Response header values like `Location` and `Retry-After` are also considered.
   *
   * Client configuration may be used to make follow-up decisions, such as:
   *
   *  * [OkHttpClient.followRedirects] must be true to follow redirects.
   *  * [OkHttpClient.followSslRedirects] must be true to follow redirects that add or remove HTTPS.
   *  * [OkHttpClient.authenticator] must respond to an authorization challenge.
   *

    }
    return Integer.MAX_VALUE
  }

  companion object {
    /**
     * How many redirects and auth challenges should we attempt? Chrome follows 21 redirects; Firefox,
     * curl, and wget follow 20; Safari follows 16; and HTTP/1.0 recommends 5.
     */
    private const val MAX_FOLLOW_UPS = 20
  }

    return wrapList(key, (List<V>) collection, null);
  }

  // Following Javadoc copied from ListMultimap.

  /**
   * {@inheritDoc}
   *
   * <p>Because the values for a given key may have duplicates and follow the insertion ordering,
   * this method returns a {@link List}, instead of the {@link Collection} specified in the {@link
   * Multimap} interface.
   */
  @Override
  public List<V> get(@ParametricNullness K key) {

If a conditional GET was successful, responses from the network and cache are merged as directed by the spec.

## Follow-up Requests

When your requested URL has moved, the webserver will return a response code like `302` to indicate the document’s new URL. OkHttp will follow the redirect to retrieve a final response.

import okhttp3.HttpUrl

/**
 * Policy on choosing which connection to use for an exchange and any retries that follow. This uses
 * the following strategies:
 *
 *  1. If the current call already has a connection that can satisfy the request it is used. Using
 *     the same connection for an initial exchange and its follow-ups may improve locality.
 *

   */
  fun onRequest(
    streamId: Int,
    requestHeaders: List<Header>,
  ): Boolean

  /**
   * The response headers corresponding to a pushed request.  When [last] is true, there are
   * no data frames to follow.
   *
   * @param streamId server-initiated stream ID: an even number.
   * @param responseHeaders minimally includes `:status`.
   * @param last when true, there is no response data.
   */
  fun onHeaders(

          ConnectResult(this, nextPlan = connectTcpNextPlan, throwable = IOException("canceled"))
        }
        connectTcpNextPlan != null -> {
          events += "plan $id needs follow-up"
          ConnectResult(this, nextPlan = connectTcpNextPlan)
        }
        else -> {
          events += "plan $id TCP connected"
          connectState = ConnectState.TCP_CONNECTED

### 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.

      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

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3

import okio.IOException

/**
 * Returns the trailers that follow an HTTP response, blocking if they aren't ready yet.
 * Implementations of this interface should respond to [Call.cancel] by immediately throwing an
 * [IOException].
 *