 @$push_to_list    = ( collector ) -> @_map_errors ( data ) => collector.push  data; return data
 @$add_to_set      = ( collector ) -> @_map_errors ( data ) => collector.add   data; return data
 #...........................................................................................................
-@$count           = -> throw new Error "not implemented"
+@$count           = -> throw new Error "µ23183 not implemented"
 @$take            = $take
 
 #-----------------------------------------------------------------------------------------------------------

@$sample = ( p = 0.5, options ) ->
  #.........................................................................................................
  unless 0 <= p <= 1
    throw new Error "expected a number between 0 and 1, got #{rpr p}"
  #.........................................................................................................
  ### Handle trivial edge cases faster (hopefully): ###
  return ( @map     ( record ) => record  ) if p == 1


# #-----------------------------------------------------------------------------------------------------------
# @$async = @remit_async = ( method ) ->
#   throw new Error "µ21653 expected a function, got a #{type}" unless ( type = CND.type_of method ) is 'function'
#   throw new Error "µ22418 ### MEH ###" unless ( arity = method.length ) is 2


#===========================================================================================================
