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
   * application interceptor, such as when implementing client-specific retries.

    // If the host exactly matches, we're done: this connection can carry the address.
    if (address.url.host == this.route().address.url.host) {
      return true // This connection is a perfect match.
    }

    // At this point we don't have a hostname match. But we still be able to carry the request if
    // our connection coalescing requirements are met. See also:

    available in those versions!


## Version 4.8.0

_2020-07-11_

 *  New: Change `HeldCertificate.Builder` to use its own ASN.1 certificate encoder. This is part
    of our effort to remove the okhttp-tls module's dependency on Bouncy Castle. We think Bouncy
    Castle is great! But it's a large dependency (6.5 MiB) and its security provider feature
    impacts VM-wide behavior.

import org.junit.jupiter.api.Tag
import org.junit.jupiter.api.Test

@Tag("Slow")
class RealWebSocketTest {
  // NOTE: Fields are named 'client' and 'server' for cognitive simplicity. This differentiation has
  // zero effect on the behavior of the WebSocket API which is why tests are only written once
  // from the perspective of a single peer.
  private val random = Random(0)
  private val client2Server = Pipe(8192L)

   * Implementations must support such concurrent calls.
   *
   * Note that cancellation is best-effort and that a call may proceed normally after it has been
   * canceled. For example, happy-path events like [requestHeadersStart] and [requestHeadersEnd] may
   * occur after a call is canceled. Typically cancellation takes effect when an expensive I/O
   * operation is required.
   *

  fun requestBodyThrowsUnrelatedToNetwork_HTTP2() {
    enableProtocol(Protocol.HTTP_2)
    requestBodyThrowsUnrelatedToNetwork()
  }

  /**
   * This test cancels the call just after the response body ends. In effect we end up with a
   * connection that returns to the connection pool with the underlying socket closed. This relies
   * on an implementation detail so it might not be a valid test case in the future.
   */
  @Test

   * 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.
   *

## Connection Pool

A primary responsibility for any HTTP client is to efficiently manage network connections. Creating and establishing new connections require a fair amount of overhead and added latency. OkHttp will make every effort to reuse existing connections to avoid this overhead and added latency.

    server.enqueue(MockResponse().setBody("response"))
    val url = server.url("/").toUrl()
    val connection = url.openConnection() as HttpURLConnection
    connection.setDoOutput(true)
    connection.setRequestProperty("Expect", "100-Continue")
    connection.outputStream.write("request".toByteArray(StandardCharsets.UTF_8))
    val inputStream = connection.inputStream

        // If there's a "Expect: 100-continue" header on the request, wait for a "HTTP/1.1 100
        // Continue" response before transmitting the request body. If we don't get that, return
        // what we did get (such as a 4xx response) without ever transmitting the request body.
        if ("100-continue".equals(request.header("Expect"), ignoreCase = true)) {
          exchange.flushRequest()