anchor.diff:    ///
     ///> live |> samplesAfter ticks
     ///
  +  /// However, a lazified stream, assuming there is enough CPU time to consume
  +  /// elements from the live stream, never internally holds to an arbitrary
  +  /// number of stream conses.
  +  ///
     /// `pullOn ts xs` is equivalent to `zipWithFun (fun _ x -> x) ts xs`.
   #endif
     val pullOn: ticks: Stream<_> -> Stream<'x> -> Stream<'x>
  
positive.code:   ///
    /// to produce a stream of button clicks.  The `Stream.Src.tap` function
    /// returns the generated stream, which can then be manipulated using stream
    /// combinators.
    ///
    /// Here is a silly example.  We could write a stream combinator that counts
    /// the number of events within a given timeout period:
  
negative.code: #endif
    val switch: Stream<'x> -> Stream<'x> -> Stream<'x>
  
    /// `switchTo lhs rhs` is equivalent to `switch rhs lhs`.
  #if DOC
    ///
    /// `switchTo` is designed to be used in pipelines:
    ///
    ///> firstStream
    ///> |> switchTo otherStream
  #endif
    val switchTo: Stream<'x> -> Stream<'x> -> Stream<'x>
  
  