/**
     * Creates a new event source and immediately returns it. Creating an event source initiates an
     * asynchronous process to connect the socket. Once that succeeds or fails, `listener` will be
     * notified. The caller must cancel the returned event source when it is no longer in use.
     */
    fun newEventSource(
      request: Request,
      listener: EventSourceListener,
    ): EventSource
  }

import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;

public final class PostFile {
  public static final MediaType MEDIA_TYPE_MARKDOWN
      = MediaType.get("text/x-markdown; charset=utf-8");

  private final OkHttpClient client = new OkHttpClient();

  public void run() throws Exception {
    File file = new File("README.md");

    Request request = new Request.Builder()

import okhttp3.RequestBody;
import okhttp3.Response;
import okio.BufferedSink;

public final class PostStreaming {
  public static final MediaType MEDIA_TYPE_MARKDOWN
      = MediaType.get("text/x-markdown; charset=utf-8");

  private final OkHttpClient client = new OkHttpClient();

  public void run() throws Exception {
    RequestBody requestBody = new RequestBody() {
      @Override public MediaType contentType() {

  // These properties are guarded by [lock].

  /**
   * If true, no new exchanges can be created on this connection. It is necessary to set this to
   * true when removing a connection from the pool; otherwise a racing caller might get it from the
   * pool when it shouldn't. Symmetrically, this must always be checked before returning a
   * connection from the pool.
   *
   * Once true this is always true. Guarded by this.
   */

      } else {
        return EventListener.NONE;
      }
    }
  };

  ...
}
```

### Events with Failures

When an operation fails, a failure method is called. This is `connectFailed()` for failures while building a connection to the server, and `callFailed()` when the HTTP call fails permanently. When a failure happens it is possible that a `start` event won’t have a corresponding `end` event.

   */
  open fun configureTlsExtensions(
    sslSocket: SSLSocket,
    hostname: String?,
    protocols: List<@JvmSuppressWildcards Protocol>,
  ) {
  }

  /** Called after the TLS handshake to release resources allocated by [configureTlsExtensions]. */
  open fun afterHandshake(sslSocket: SSLSocket) {
  }

  /** Returns the negotiated protocol, or null if no protocol was negotiated. */

    server.enqueue(
      MockResponse(
        code = 401,
        headers =
          headersOf(
            "WWW-Authenticate",
            "Basic realm=\"protected area\", charset=\"UTF-8\"",
          ),
        body = "Please authenticate with UTF-8.",
      ),
    )
    server.enqueue(
      MockResponse(
        code = 401,
        headers =
          headersOf(

      .assertRequestHeader("Accept-Charset", "UTF-8") // Because of Vary on Accept-Charset.
      .assertRequestHeader("If-None-Match") // This wasn't present in the original request.
      .assertSentRequestAtMillis(request1SentAt, request1ReceivedAt)
      .assertReceivedResponseAtMillis(request1SentAt, request1ReceivedAt)

    // Check the network response. It has the caller's request, plus some caching headers.

  fun statementStartsAndStops() {
    val called = AtomicBoolean()
    val statement =
      server.apply(
        object : Statement() {
          override fun evaluate() {
            called.set(true)
            server.url("/").toUrl().openConnection().connect()
          }
        },
        Description.EMPTY,
      )
    statement.evaluate()
    assertThat(called.get()).isTrue()
    try {

      "UTF-8",
      noCharset.charset(Charsets.UTF_8)!!.name(),
    )
    assertEquals(
      "US-ASCII",
      noCharset.charset(Charsets.US_ASCII)!!.name(),
    )
    val charset = parse("text/plain; charset=iso-8859-1")
    assertEquals(
      "ISO-8859-1",
      charset.charset(Charsets.UTF_8)!!.name(),
    )
    assertEquals(
      "ISO-8859-1",
      charset.charset(Charsets.US_ASCII)!!.name(),
    )
  }