anchor.diff:  
           map.MapPartition partitioner
   
  -*)
  
positive.code:     /// Returns true if 'other' is a submap of this map.
      member this.IsSubmapOfBy (predicate, other : HashMap<'Key, 'T>) : bool =
          PatriciaHashMap.IsSubmapOfBy predicate other.Trie trie
  
      /// The HashMap containing the given binding.
      static member Singleton (key : 'Key, value : 'T) : HashMap<'Key, 'T> =
          HashMap (
              Lf (uint32 key, value))
  
      /// Returns a new HashMap made from the given bindings.
      static member OfSeq (source : seq<'Key * 'T>) : HashMap<'Key, 'T> =
  
negative.code:     member __.Items
          with get () : KeyValuePair<'Key, 'T>[] =
              map.ToKvpArray ()
  
  
  /// Functional programming operators related to the HashMap type.
  [<RequireQualifiedAccess; CompilationRepresentation(CompilationRepresentationFlags.ModuleSuffix)>]
  module HashMap =
      /// The empty map.
      [<CompiledName("Empty")>]
      let empty<'Key, 'T when 'Key : equality> =
          HashMap<'Key, 'T>.Empty
  
      /// Is the map empty?
  