anchor.diff:  
         let record = { id = 1; map = map }
         let doc = Bson.serialize record
  -      
  +
         match Bson.deserialize<RecordWithMap> doc with
         | { id = 1; map = x } -> 
           match x.["Hello"], x.["Anyone"] with 
  
positive.code: type RecordWithGenericUnion<'t> = { Id: int; GenericUnion: Maybe<'t> }
  type RecordWithDateTime = { id: int; created: DateTime }
  type RecordWithMap = { id : int; map: Map<string, string> }
  let pass() = Expect.isTrue true "passed"
  let fail() = Expect.isTrue false "failed"
    
  
negative.code:       | { id = 1; age = 19 } -> pass()
        | otherwise -> fail()
  
      testCase "record with array" <| fun _ ->
        let record = { id = 1; arr = [| 1 .. 5 |] }
        let doc = Bson.serialize record
        match Bson.deserialize<RecordWithArray> doc with
        | { id = 1; arr = [| 1;2;3;4;5 |] } -> pass()
        | otherwise -> fail()
  
      testCase "record with map" <| fun _ -> 
        let map = 
  