anchor.diff:  block cache, which can be found on the `/metrics` endpoint of the web UI. An
   example set:
   
  -[source,json]
   ----
   {
     "name": "block_cache_inserts",
  
positive.code: -69.195.159.158  128.138.140.44   2 u    9   64    1   53.885   -0.016   0.013
  *216.218.254.202 .CDMA.           1 u    6   64    1    1.475   -0.400   0.012
  +129.250.35.250  249.224.99.213   2 u    7   64    1    1.342   -0.640   0.018
   45.76.244.193   216.239.35.4     2 u    6   64    1   17.380   -0.754   0.051
   69.89.207.199   212.215.1.157    2 u    5   64    1   57.796   -3.411   0.059
   171.66.97.126   .GPSs.           1 u    4   64    1    1.024   -0.374   0.018
   66.228.42.59    211.172.242.174  3 u    3   64    1   72.409    0.895   0.964
   91.189.89.198   17.253.34.125    2 u    2   64    1  135.195   -0.329   0.171
   162.210.111.4   216.218.254.202  2 u    1   64    1   28.570    0.693   0.306
   199.102.46.80   .GPS.            1 u    2   64    1   55.652   -0.039   0.019
   91.189.89.199   17.253.34.125    2 u    1   64    1  135.265   -0.413   0.037
  $ ntpq -nc opeers
       remote           local      st t when poll reach   delay   offset    disp
  ==============================================================================
  
negative.code:   time constant 10, precision 0.001 us, tolerance 500 ppm,
  ----
  
  Note the following most important pieces of output:
  
  - `maximum error 22455 us`: this value is well under the 10-second maximum
    error required by Kudu.
  - `status 0x2001 (PLL,NANO)`: this indicates the local clock is synchronized
    with the true time up to the maximum error above
  
  In contrast, a system with unsynchronized local clock would report something
  like the following:
  
  ----
  ntp_gettime() returns code 5 (ERROR)
  