// Choice here is between failing with a correct RuntimeException
        // or mostly silently with an IOException
        url = urlLine.toHttpUrlOrNull() ?: throw IOException("Cache corruption for $urlLine").also {
          Platform.get().log("cache corruption", WARN, it)
        }
        requestMethod = source.readUtf8LineStrict()
        val varyHeadersBuilder = Headers.Builder()
        val varyRequestHeaderLineCount = readInt(source)