OkHttp Server-Sent Events
=========================

Experimental support for server-sent events.
API is not considered stable and may change at any time.

### Download

```kotlin
testImplementation("com.squareup.okhttp3:okhttp-sse:5.1.0")

    client.webSocket!!.finishReader()
    taskFaker.runTasks()
    assertThat(client.closed).isTrue()
    client.listener.assertFailure(
      ProtocolException::class.java,
      "Server-sent frames must not be masked.",
    )
    server.listener.assertClosing(1000, "Hello")
    server.listener.assertExhausted() // Client should not have sent second close.
  }

  @Test

        return new CurlRequest(Method.GET, url);
    }

    /**
     * Creates a new CurlRequest with the HTTP POST method for the specified URL.
     *
     * @param url the URL to which the POST request will be sent
     * @return a new CurlRequest object configured with the POST method and the specified URL
     */
    public static CurlRequest post(final String url) {
        return new CurlRequest(Method.POST, url);
    }

   *
   * A push promise contains all the headers that pertain to a server-initiated request, and a
   * `promisedStreamId` to which response frames will be delivered. Push promise frames are sent as
   * a part of the response to `streamId`. The `promisedStreamId` has a priority of one greater than
   * `streamId`.
   *
   * @param streamId client-initiated stream ID.  Must be an odd number.

* HTTP/2 - [RFC 9113](https://datatracker.ietf.org/doc/html/rfc9113)
* Websockets - [RFC 6455](https://datatracker.ietf.org/doc/html/rfc6455)
* SSE - [Server-sent events](https://html.spec.whatwg.org/multipage/server-sent-events.html#server-sent-events)

Where the spec is ambiguous, OkHttp follows modern user agents such as popular Browsers or common HTTP Libraries.

      // Masked payloads must be read on the server. Unmasked payloads must be read on the client.
      throw ProtocolException(
        if (isClient) {
          "Server-sent frames must not be masked."
        } else {
          "Client-sent frames must be masked."
        },
      )
    }

    // Get frame length, optionally reading from follow-up bytes if indicated by special values.

   *
   * The values of this attribute determine whether this cookie is sent for cross-site calls:
   *
   *  - "Strict": the cookie is omitted when the subject URL is an embedded resource or a
   *    potentially-destructive navigation.
   *
   *  - "Lax": the cookie is omitted when the subject URL is an embedded resource. It is sent for
   *    potentially-destructive navigation. This is the default value.
   *

  private var failed = false

  /** Total number of pings sent by this web socket. */
  private var sentPingCount = 0

  /** Total number of pings received by this web socket. */
  private var receivedPingCount = 0

  /** Total number of pongs received by this web socket. */
  private var receivedPongCount = 0

  /** True if we have sent a ping that is still awaiting a reply. */
  private var awaitingPong = false

package okhttp3

import java.io.IOException
import okhttp3.Interceptor.Chain
import okio.Buffer
import okio.BufferedSink
import okio.ForwardingSink
import okio.Sink
import okio.buffer

/** Rewrites the request body sent to the server to be all uppercase.  */
class UppercaseRequestInterceptor : Interceptor {
  @Throws(IOException::class)
  override fun intercept(chain: Chain): Response = chain.proceed(uppercaseRequest(chain.request()))

   * events.
   */
  open fun onOpen(
    eventSource: EventSource,
    response: Response,
  ) {
  }

  /**
   * Invoked when a new event has been sent to the client.
   *
   * @param id The `id` line of the event, might be null.
   * @param type The `event` line of the event, might be null.
   * @param data The `data` line of the event.
   */
  open fun onEvent(