
  [;1m-spec erlang:system_monitor(Arg) -> MonSettings[0m
  [;1m                               when[0m
  [;1m                                   Arg ::[0m
  [;1m                                       undefined | {MonitorPid, Options},[0m
  [;1m                                   MonSettings ::[0m
  [;1m                                       undefined | {MonitorPid, Options},[0m
  [;1m                                   MonitorPid :: pid(),[0m
  [;1m                                   Options :: [system_monitor_option()].[0m

  Types:
    -type system_monitor_option() ::
          busy_port | busy_dist_port |
          {long_gc, non_neg_integer()} |
          {long_schedule, non_neg_integer()} |
          {large_heap, non_neg_integer()}.

  When called with argument [;;4mundefined[0m, all system performance
  monitoring settings are cleared.

  Calling the function with [;;4m{MonitorPid, Options}[0m as argument is
  the same as calling [;;4merlang:system_monitor(MonitorPid, Options)[0m.

  Returns the previous system monitor settings just like [;;4m[0m
  [;;4merlang:system_monitor/0[0m.
