if (result < 0L || result > Integer.MAX_VALUE || line.isNotEmpty()) {
          throw IOException("expected an int but was \"$result$line\"")
        }
        return result.toInt()
      } catch (e: NumberFormatException) {
        throw IOException(e.message)
      }
    }

    /**
     * Returns true if none of the Vary headers have changed between [cachedRequest] and