anchor.diff:  
     // Exceptions
   
  -  /// Preliminary and subject to change.
  +  /// Returns a stream that produces the same sequence of elements as the given
  +  /// stream.  If the given stream fails, a new stream is constructed by calling
  +  /// the given function and that stream becomes the remainder of the stream.
     val catch: (exn -> #Stream<'x>) -> Stream<'x> -> Stream<'x>
   
     /// Returns a stream that is just like the given stream except that just
  
positive.code: 
    // Timing
  
    /// Preliminary and subject to change.
    val sample: ticks: Stream<_> -> Stream<'x> -> Stream<'x>
  
    /// Preliminary and subject to change.
    val throttle: timeout: Alt<_> -> Stream<'x> -> Stream<'x>
  
    /// Preliminary and subject to change.
    val hold: timeout: Job<_> -> Stream<'x> -> Stream<'x>
  
    /// Preliminary and subject to change.
  
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.
  