*  Fix: Include the header `Accept: text/event-stream` for SSE calls. This header is not added if
    the request already contains an `Accept` header.

 *  Fix: Don't crash with a `NullPointerException` if a server sends a close while we're sending a
    ping. OkHttp had a race condition bug.


## Version 4.6.0

_2020-04-28_

 *  Fix: Follow HTTP 307 and 308 redirects on methods other than GET and POST. We're reluctant to

 *     .build();
 * ```
 *
 * ## Force a Cache Response
 *
 * Sometimes you'll want to show resources if they are available immediately, but not otherwise.
 * This can be used so your application can show *something* while waiting for the latest data to be
 * downloaded. To restrict a request to locally-cached resources, add the `only-if-cached`
 * directive:
 *
 * ```java
 * Request request = new Request.Builder()

    // Make an SSL Tunnel on the first message pair of each SSL + proxy connection.
    val url = route.address.url
    val requestLine = "CONNECT ${url.toHostHeader(includeDefaultPort = true)} HTTP/1.1"
    while (true) {
      val source = this.source!!
      val sink = this.sink!!
      val tunnelCodec =
        Http1ExchangeCodec(
          // No client for CONNECT tunnels:
          client = null,

 * deterministic.
 *
 * This class ensures that at most one thread is running at a time. This is initially the JUnit test
 * thread, which yields its execution privilege while calling [runTasks], [runNextTask], or
 * [advanceUntil]. These functions don't return until the task threads are all idle.
 *
 * Task threads release their execution privilege in these ways:
 *

  private val readyQueues = mutableListOf<TaskQueue>()

  private val runnable: Runnable =
    object : Runnable {
      override fun run() {
        var incrementedRunCallCount = false
        while (true) {
          val task =
            ******@****.***ck {
              if (!incrementedRunCallCount) {
                incrementedRunCallCount = true
                runCallCount++
              }

      sink.close()
    }
  }

  @Throws(IOException::class)
  private fun writeContinuationFrames(
    streamId: Int,
    byteCount: Long,
  ) {
    var byteCount = byteCount
    while (byteCount > 0L) {
      val length = minOf(maxFrameSize.toLong(), byteCount)
      byteCount -= length
      frameHeader(
        streamId = streamId,
        length = length.toInt(),

    routePlanner.autoGeneratePlans = true
    val address = routePlanner.address
    val pool = routePlanner.pool

    // Add a connection to the pool that won't expire for a while
    routePlanner.defaultConnectionIdleAtNanos = expireLater
    setPolicy(pool, address, ConnectionPool.AddressPolicy(1))
    assertThat(pool.connectionCount()).isEqualTo(1)

    clientListener.assertOpen()

    // Send messages until the client's outgoing buffer overflows!
    val message: ByteString = ByteString.of(*ByteArray(1024 * 1024))
    var messageCount: Long = 0
    while (true) {
      val success = webSocket.send(message)
      if (!success) break
      messageCount++
      val queueSize = webSocket.queueSize()
      assertThat(queueSize).isBetween(0L, messageCount * message.size)

    if (byteCount == 0L) {
      writer.data(outFinished, streamId, buffer, 0)
      return
    }

    var byteCount = byteCount
    while (byteCount > 0L) {
      var toWrite: Int
      this.withLock {
        try {
          while (writeBytesTotal >= writeBytesMaximum) {
            // Before blocking, confirm that the stream we're writing is still open. It's possible

    var request = chain.request
    val call = realChain.call
    var followUpCount = 0
    var priorResponse: Response? = null
    var newRoutePlanner = true
    var recoveredFailures = listOf<IOException>()
    while (true) {
      call.enterNetworkInterceptorExchange(request, newRoutePlanner, chain)

      var response: Response
      var closeActiveExchange = true
      try {
        if (call.isCanceled()) {