       throw new Error "µ30903 on_end called more than once" if count > 1
       help 'on_end'
       @queue 'yo'
-      @queue end_sym
+      @queue PS.symbols.end
     return pull_through on_data, on_end
   #.........................................................................................................
   demo = -> new Promise ( resolve ) ->

    return map ( d ) ->
      debug '20922', d
      # debug '20922', send
      if d is end_sym
        clearInterval timer
      return d
  #.........................................................................................................
  $terminate_on_end_symbol = ->
    return P.asyncMap ( d, handler ) -> if d is end_sym then handler true else handler null, d
  #.........................................................................................................
  $end_as_symbol = ->
    count = 0

  pull_through    = require 'pull-through'
  new_pushable    = require 'pull-pushable'
  map             = require '../_map_errors'
  #.........................................................................................................
  $keep_open_with_timer = ->
    timer = every 1, -> process.stdout.write '*'
