anchor.diff:  err_resource_constraint() ->
       err(wait, 'resource-constraint', 500).
   
  --spec err_resource_constraint(binary(), binary()) -> stanza_error().
  +-spec err_resource_constraint(reason_text(), lang()) -> stanza_error().
   err_resource_constraint(Text, Lang) ->
       err(wait, 'resource-constraint', 500, Text, Lang).
   
  
positive.code: err_internal_server_error() ->
      err(wait, 'internal-server-error', 500).
  
  -spec err_internal_server_error(binary(), binary()) -> stanza_error().
  err_internal_server_error(Text, Lang) ->
      err(wait, 'internal-server-error', 500, Text, Lang).
  
  
negative.code: serr_reset() ->
      serr('reset').
  
  -spec serr_reset(reason_text(), lang()) -> stream_error().
  serr_reset(Text, Lang) ->
      serr('reset', Text, Lang).
  
  