anchor.diff:      val create: unit -> Src<'x>
   
       /// Appends a new value to the end of the generated stream.  This operation
  -    /// is atomic and can be safely used from multiple parallel jobs.
  +    /// is atomic and non-blocking and can be safely used from multiple parallel
  +    /// jobs.
       val value: Src<'x> -> 'x -> Job<unit>
   
       /// Terminates the stream with an error.  The given exception is raised in
  
positive.code: 
    /// Represents an imperative source of a stream of values called a stream
    /// source.
    type Src<'x>
  
    /// Operations on stream sources.
  
negative.code:   /// streams.  For example,
    ///
    ///> let fibs: Stream<BigInteger> =
    ///>   let rec lp f0 f1 = cons f0 << delay <| fun () -> lp f1 (f0 + f1)
    ///>   lp 0I 1I
    ///
    /// is the stream of all fibonacci numbers.
  