anchor.diff:      let Map16 = 0xdeuy
       [<Literal>]
       let Map32 = 0xdfuy
  +    let NegativeFixNum = [| 0xe0uy..0xffuy |]
   
   type Value =
       | Nil
  
positive.code: module MsgPack 
  
  open System
  
  module private DataType =
      let FixMap = [| 0x80uy..0x8fuy |]
      let FixArray = [| 0x90uy..0x9fuy |]
      let FixString = [| 0xa0uy..0xbfuy |]
  
negative.code: 
          let res = pack bytes (Array.length bytes)
          match Array.length res with
          | 1 when Array.exists ((=) res.[0]) DataType.PositiveFixNum -> res
          | 1 -> [| yield DataType.UInt8; yield res.[0]  |]
          | 2 -> [| yield DataType.UInt16; yield! res |]
          | 4 -> [| yield DataType.UInt32; yield! res |]
          | 8 -> [| yield DataType.UInt64; yield! res |]
  