throws IOException {
        if (conn == null)
            return;

        String statusLine = "HTTP/1.1 " + code + " " + message;
        when(conn.getResponseCode()).thenReturn(code);
        when(conn.getResponseMessage()).thenReturn(message);
        when(conn.getHeaderField(0)).thenReturn(statusLine);

        // Mock getHeaderFields to return our headers

    }

    try {
      val statusLine = StatusLine.parse(headersReader.readLine())

      val responseBuilder =
        Response
          .Builder()
          .protocol(statusLine.protocol)
          .code(statusLine.code)
          .message(statusLine.message)
          .headers(headersReader.readHeaders())

      return when {
        expectContinue && statusLine.code == HTTP_CONTINUE -> {
          null

          varyHeadersBuilder.addLenient(source.readUtf8LineStrict())
        }
        varyHeaders = varyHeadersBuilder.build()

        val statusLine = StatusLine.parse(source.readUtf8LineStrict())
        protocol = statusLine.protocol
        code = statusLine.code
        message = statusLine.message
        val responseHeadersBuilder = Headers.Builder()
        val responseHeaderLineCount = readInt(source)