
  [;1m-spec unlink(Id) -> true when Id :: pid() | port().[0m

  Removes a link between the calling process and another process or
  a port identified by [;;4mId[0m. We will from here on call the
  identified process or port unlinkee.

  A link can be set up using the [;;4mlink/1[0m BIF. For more information
  on links and exit signals due to links, see the Processes
  chapter in the Erlang Reference Manual:

   • Links

   • Sending Exit Signals

   • Receiving Exit Signals

  Once [;;4munlink(Id)[0m has returned, it is guaranteed that the link
  between the caller and the unlinkee has no effect on the caller in
  the future (unless the link is setup again). Note that if the
  caller is trapping exits, an [;;4m{'EXIT', Id, ExitReason}[0m message
  due to the link may have been placed in the message queue of the
  caller before the [;;4munlink(Id)[0m call completed. Also note that the [;;4m[0m
  [;;4m{'EXIT', Id, ExitReason}[0m message may be the result of the link,
  but may also be the result of the unlikee sending the caller an
  exit signal by calling the [;;4mexit/2[0m BIF. Therefore, it may or may
  not be appropriate to clean up the message queue after a call to [;;4m[0m
  [;;4munlink(Id)[0m as follows, when trapping exits:

    unlink(Id),
    receive
        {'EXIT', Id, _} ->
            true
    after 0 ->
            true
    end

  The link removal is performed asynchronously. If such a link does
  not exist, nothing is done. A detailed description of the link
  protocol can be found in the Distribution Protocol chapter of
  the ERTS User's Guide.

  Failure: [;;4mbadarg[0m if [;;4mId[0m does not identify a process or a node
  local port.
