fun interface Authenticator {
  /**
   * Returns a request that includes a credential to satisfy an authentication challenge in
   * [response]. Returns null if the challenge cannot be satisfied.
   *
   * The route is best effort, it currently may not always be provided even when logically
   * available. It may also not be provided when an authenticator is re-used manually in an

    coders call this and we don't want their users to suffer.


## Version 4.0.0

_2019-06-26_

**This release upgrades OkHttp to Kotlin.** We tried our best to make fast and safe to upgrade
from OkHttp 3.x. We wrote an [upgrade guide][upgrading_to_okhttp_4] to help with the migration and a
[blog post][okhttp4_blog_post] to explain it.

 * and initializing on first use.
 *
 * We use this because eager classpath checks cause confusion and excessive logging in Android,
 * and we can't rely on classnames after proguard, so are probably best served by falling through
 * to a situation of trying our least likely noisiest options.
 */
class DeferredSocketAdapter(private val socketAdapterFactory: Factory) : SocketAdapter {
  private var delegate: SocketAdapter? = null

   * scheduled. If the task is already in the queue, the earliest execution time is used.
   *
   * The target execution time is implemented on a best-effort basis. If another task in this queue
   * is running when that time is reached, that task is allowed to complete before this task is
   * started. Similarly the task will be delayed if the host lacks compute resources.
   *

    responseCode != HTTP_NOT_MODIFIED
  ) {
    return true
  }

  // If the Content-Length or Transfer-Encoding headers disagree with the response code, the
  // response is malformed. For best compatibility, we honor the headers.
  if (headersContentLength() != -1L ||
    "chunked".equals(header("Transfer-Encoding"), ignoreCase = true)
  ) {
    return true
  }

  return false
}

 *    number of prefixes (`us-west.www.publicobject.com`, `www.publicobject.com`) including no
 *    prefix at all (`publicobject.com`). For most applications this is the best way to configure
 *    certificate pinning.
 *
 *  * **Exactly one subdomain**: Use a single asterisk like `*.publicobject.com` to match exactly

 * the updated response if it has changed, or a short 'not modified' response if the client's copy
 * is still valid. Such responses increment both the network count and hit count.
 *
 * The best way to improve the cache hit rate is by configuring the web server to return cacheable
 * responses. Although this client honors all [HTTP/1.1 (RFC 7234)][rfc_7234] cache headers, it
 * doesn't cache partial responses.
 *

          }

          connectionUser.dnsEnd(socketHost, result)
          result
        }

      // Try each address for best behavior in mixed IPv4/IPv6 environments.
      val orderedAddresses =
        when {
          fastFallback -> reorderForHappyEyeballs(addresses)
          else -> addresses
        }

    requests with the same POST data get the same cache entry.

 *  New: `HttpLoggingInterceptor.redactQueryParams()` configures the query parameters to redact
    in logs. For best security, don't put sensitive information in query parameters.

 *  New: `ConnectionPool.setPolicy()` configures a minimum connection pool size for a target
    address. Use this to proactively open HTTP connections.

import org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement

/**
 * Factory for [calls][Call], which can be used to send HTTP requests and read their responses.
 *
 * ## OkHttpClients Should Be Shared
 *
 * OkHttp performs best when you create a single `OkHttpClient` instance and reuse it for all of
 * your HTTP calls. This is because each client holds its own connection pool and thread pools.