*
 * <p>To react to events, we recommend a reactive-streams framework like <a
 * href="https://github.com/ReactiveX/RxJava/wiki">RxJava</a> (supplemented with its <a
 * href="https://github.com/ReactiveX/RxAndroid">RxAndroid</a> extension if you are building for
 * Android) or <a href="https://projectreactor.io/">Project Reactor</a>. (For the basics of
 * translating code from using an event bus to using a reactive-streams framework, see these two

    <inspection_tool class="UnstableApiUsage" enabled="true" level="WARNING" enabled_by_default="true">
      <option name="unstableApiAnnotations">
        <set>
          <option value="io.reactivex.annotations.Beta" />
          <option value="io.reactivex.annotations.Experimental" />
          <option value="org.apache.http.annotation.Beta" />
          <option value="org.gradle.api.Incubating" />

      <option name="unstableApiAnnotations">
        <set>
          <option value="com.google.common.annotations.Beta" />
          <option value="io.reactivex.annotations.Beta" />
          <option value="io.reactivex.annotations.Experimental" />
          <option value="org.apache.http.annotation.Beta" />
          <option value="org.jetbrains.annotations.ApiStatus.Experimental" />

 */
package okhttp3

import java.io.IOException
import okhttp3.internal.authenticator.JavaNetAuthenticator

/**
 * Performs either **preemptive** authentication before connecting to a proxy server, or
 * **reactive** authentication after receiving a challenge from either an origin web server or proxy
 * server.
 *
 * ## Preemptive Authentication
 *