.writeUtf8(": ")
        .writeUtf8(headers.value(i))
        .writeUtf8("\r\n")
    }
    sink.writeUtf8("\r\n")
    state = STATE_OPEN_REQUEST_BODY
  }

  override fun readResponseHeaders(expectContinue: Boolean): Response.Builder? {
    check(
      state == STATE_OPEN_REQUEST_BODY ||
        state == STATE_WRITING_REQUEST_BODY ||
        state == STATE_READ_RESPONSE_HEADERS,
    ) {
      "state: $state"

        final URI uri = root.resolve(key.getHashCode());
        HttpPut httpPut = new HttpPut(uri);
        if (useExpectContinue) {
            httpPut.setHeader(HTTP.EXPECT_DIRECTIVE, HTTP.EXPECT_CONTINUE);
        }
        httpPut.addHeader(HttpHeaders.CONTENT_TYPE, BUILD_CACHE_CONTENT_TYPE);
        requestCustomizer.customize(httpPut);

        httpPut.setEntity(new AbstractHttpEntity() {