anchor.diff:              parseEllipsis() // tolerate ... or {...}
           ensure(i < s.Length && s.[i] = '}')
           i <- i + 1
  -        let arr = pairs.ToArray()
  -        pairs.Clear()
  -        JsonValue.Record(arr)
  +        JsonValue.Record(pairs.ToArray())
   
       and parseArray() =
           ensure(i < s.Length && s.[i] = '[')
           i <- i + 1
           skipWhitespace()
  +        let vals = ResizeArray<_>()
           if i < s.Length && s.[i] <> ']' then
               vals.Add(parseValue())
               skipWhitespace()
  
positive.code:     let mutable i = 0
      let s = jsonText
  
      // pre-allocate buffers for strings, arrays and records
      let buf = StringBuilder()
      let pairs = ResizeArray<_>()
      let vals = ResizeArray<_>()
  
      // Helper functions
      let skipWhitespace() =
  
negative.code:         ensure(i < s.Length && s.[i] = '{')
          i <- i + 1
          skipWhitespace()
          let pairs = ResizeArray<_>()
          if i < s.Length && s.[i] = '"' then
              pairs.Add(parsePair())
              skipWhitespace()
  