anchor.diff:    ///> let ( *<+=>- ) qCh rI2q = qCh *<+=>= (rI2q >> result)
   #endif
     val inline ( *<+=>- ): Ch<'q> -> (IVar<'r>                  ->      'q)  -> Alt<'r>
  -  
  +
  +  //# Message passing
  +
     /// Creates an alternative that, at instantiation time, offers to give the
     /// given value on the given channel, and becomes available when another job
     /// offers to take the value.  `xCh *<- x` is equivalent to `Ch.give xCh x`.
  
positive.code: #endif
  module Infixes =
  
    // Message passing -----------------------------------------------------------
  
    /// Creates an alternative that, using the given job constructor, constructs a
    /// query with a reply channel and a nack, sends it to the query channel and
  
negative.code:   /// A memoizing version of `>->!`.
    val inline ( >->*! ): ('x -> #Job<_>)  ->             exn  -> 'x -> Promise<_>
  
    //# Pairing
  
    /// Creates a job that runs the given two jobs and then returns a pair of
    /// their results.  `xJ <&> yJ` is equivalent to `xJ >>= fun x -> yJ >>= fun y
  