anchor.diff:  
     // Timing
   
  -  /// Preliminary and subject to change.
  -  val sample: ticks: Stream<_> -> Stream<'x> -> Stream<'x>
  -
  -  /// Preliminary and subject to change.
  +  /// `sample ticks elems` returns a stream that produces each `elem` that is
  +  /// followed by a `tick`.  Excess elements from both streams are skipped.  In
  +  /// other words, `elem` followed by `elem` and `tick` followed by `tick` is
  +  /// skipped.
  +  val sample: ticks: Stream<_> -> elems: Stream<'x> -> Stream<'x>
  +
  +  /// Returns a stream that produces elements from the given stream so that an
  +  /// element is produced after the given timeout unless a new element is
  +  /// produced by the given stream in which case the timeout is restarted.  Note
  +  /// that if the given stream produces elements more frequently than the
  +  /// timeout, the returned stream never produces any elements.
     val throttle: timeout: Alt<_> -> Stream<'x> -> Stream<'x>
   
  -  /// Preliminary and subject to change.
  +  /// Returns a stream that produces elements from the given stream so that
  +  /// after an element is produced by the given stream, a timeout is started and
  +  /// the latest element produced by the stream is produced when the timeout
  +  /// expires.
     val hold: timeout: Job<_> -> Stream<'x> -> Stream<'x>
   
     /// Preliminary and subject to change.
  
positive.code: 
    // Exceptions
  
    /// Preliminary and subject to change.
    val catch: (exn -> #Stream<'x>) -> Stream<'x> -> Stream<'x>
  
    /// Returns a stream that is just like the given stream except that just
  
negative.code: 
    /// Returns a job that creates an alternative through which all the values of
    /// the stream generated after the point at which the alternative has been
    /// created can be read.  See also: `indefinitely`.
    val values: Stream<'x> -> Job<Alt<'x>>
  
    /// Preliminary and subject to change.
  