ensure MarshalJSON always output valid JSON by serializing math.Inf to 'null'
ensure MarshalJSON always output valid JSON by serializing math.Inf to 'null'

  name         old time/op  new time/op  delta
  MarshalJSON  16.5ms ± 0%  16.2ms ± 0%   ~     (p=0.333 n=2+2)

errx/carbonapi,errx/carbonapi,arodland/carbonapi,dgryski/carbonapi,nnuss/carbonapi,lyft/carbonapi