* @param source location of data corresponding with this stream ID.
   * @param byteCount number of bytes to read or skip from the source.
   * @param last when true, there are no data frames to follow.
   */
  @Throws(IOException::class)
  fun onData(
    streamId: Int,
    source: BufferedSource,
    byteCount: Int,
    last: Boolean,
  ): Boolean

  /** Indicates the reason why this stream was canceled. */

    return object : ForwardingSource(source) {
      @Throws(IOException::class)
      override fun read(
        sink: Buffer,
        byteCount: Long,
      ): Long {
        val buffer = Buffer()
        val read = delegate.read(buffer, byteCount)
        if (read != -1L) {
          sink.write(buffer.readByteString().toAsciiUppercase())
        }
        return read
      }
    }
  }

) : ForwardingSink(delegate) {
  private var hasErrors = false

  override fun write(
    source: Buffer,
    byteCount: Long,
  ) {
    if (hasErrors) {
      source.skip(byteCount)
      return
    }
    try {
      super.write(source, byteCount)
    } catch (e: IOException) {
      hasErrors = true
      onException(e)
    }
  }

  override fun flush() {
    if (hasErrors) {

      .assertLogMatch(Regex("""requestBodyEnd: byteCount=6"""))
      .assertLogMatch(Regex("""responseHeadersStart"""))
      .assertLogMatch(Regex("""responseHeadersEnd: Response\{protocol=http/1\.1, code=200, message=OK, url=$url\}"""))
      .assertLogMatch(Regex("""responseBodyStart"""))
      .assertLogMatch(Regex("""responseBodyEnd: byteCount=0"""))
      .assertLogMatch(Regex("""connectionReleased"""))

  /**
   * Peeks up to [byteCount] bytes from the response body and returns them as a new response
   * body. If fewer than [byteCount] bytes are in the response body, the full response body is
   * returned. If more than [byteCount] bytes are in the response body, the returned value
   * will be truncated to [byteCount] bytes.
   *

          private var completed = false

          override fun write(
            source: Buffer,
            byteCount: Long,
          ) {
            super.write(source, byteCount)
            totalBytesWritten += byteCount
            progressListener.update(totalBytesWritten, contentLength(), completed)
          }

          override fun close() {
            super.close()

        var closed = false

        override fun close() {
          closed = true
        }

        override fun read(
          sink: Buffer,
          byteCount: Long,
        ): Long {
          check(!closed)
          return data.read(sink, byteCount)
        }

        override fun timeout(): Timeout = Timeout.NONE
      }
    return source.buffer().asResponseBody(null, -1)
  }

  private fun newResponse(

    countBytes: Boolean,
  ): Long {
    var byteCount = 0L
    val buffer: Buffer = if (countBytes) Buffer() else sink!!.buffer

    for (i in 0 until encodedNames.size) {
      if (i > 0) buffer.writeByte('&'.code)
      buffer.writeUtf8(encodedNames[i])
      buffer.writeByte('='.code)
      buffer.writeUtf8(encodedValues[i])
    }

    if (countBytes) {
      byteCount = buffer.size
      buffer.clear()
    }

 * sample of code points to detect unicode control characters commonly used in binary file
 * signatures.
 */
fun Buffer.isProbablyUtf8(): Boolean {
  try {
    val prefix = Buffer()
    val byteCount = size.coerceAtMost(64)
    copyTo(prefix, 0, byteCount)
    for (i in 0 until 16) {
      if (prefix.exhausted()) {
        break
      }
      val codePoint = prefix.readUtf8CodePoint()

    private Source source(Source source) {
      return new ForwardingSource(source) {
        long totalBytesRead = 0L;

        @Override public long read(Buffer sink, long byteCount) throws IOException {
          long bytesRead = super.read(sink, byteCount);
          // read() returns the number of bytes read, or -1 if this source is exhausted.
          totalBytesRead += bytesRead != -1 ? bytesRead : 0;