* requires us to have a DNS address for both hosts, which only happens after route planning. We
   * can't coalesce connections that use a proxy, since proxies don't tell us the origin server's IP
   * address.
   */
  private fun routeMatchesAny(candidates: List<Route>): Boolean {
    return candidates.any {
      it.proxy.type() == Proxy.Type.DIRECT &&

      isTlsFallback = isTlsFallback,
    )
  }

  override fun connectTcp(): ConnectResult {
    check(rawSocket == null) { "TCP already connected" }

    var success = false

    // Tell the call about the connecting call so async cancels work.
    user.addPlanToCancel(this)
    try {
      user.connectStart(route)

      connectSocket()
      success = true

      val pkcs8Bytes =
        pkcs8Base64Text.decodeBase64()
          ?: throw IllegalArgumentException("failed to decode private key")

      // The private key doesn't tell us its type but it's okay because the certificate knows!
      val keyType =
        when (certificate.publicKey) {
          is ECPublicKey -> "EC"
          is RSAPublicKey -> "RSA"

        type = TYPE_PING,
        flags = if (ack) FLAG_ACK else FLAG_NONE,
      )
      sink.writeInt(payload1)
      sink.writeInt(payload2)
      sink.flush()
    }
  }

  /**
   * Tell the peer to stop creating streams and that we last processed `lastGoodStreamId`, or zero
   * if no streams were processed.
   *
   * @param lastGoodStreamId the last stream ID processed, or zero if no streams were processed.

     */
    fun ping(
      ack: Boolean,
      payload1: Int,
      payload2: Int,
    )

    /**
     * The peer tells us to stop creating streams. It is safe to replay streams with
     * `ID > lastGoodStreamId` on a new connection.  In- flight streams with
     * `ID <= lastGoodStreamId` can only be replayed on a new connection if they are idempotent.

        remainingByteCount -= read

        // Move the received data to the read buffer to the reader can read it. If this source has
        // been closed since this read began we must discard the incoming data and tell the
        // connection we've done so.
        ******@****.***ck {
          if (closed) {
            receiveBuffer.clear()
          } else {
            val wasEmpty = readBuffer.size == 0L