Calling internal-default-process-sentinel from another sentinel?

["Štěpán Němec" <stepnem@gmail.com>]

For an asynchronous process I'd like to preserve the default sentinel
behaviour (insert a status message into the process's buffer, if there
is one), and only in one particular case (successful completion) add
some other functionality (follow up with a custom action).

Such a use case doesn't seem uncommon and simply calling
'internal-default-process-sentinel' from a custom sentinel would seem a
good solution, but the "internal-" prefix or the fact that such usage is
completely absent from Emacs core and very rare even in 3rd party
code[1] don't inspire confidence.

I'd appreciate advice or opinions on whether reusing
internal-default-process-sentinel is acceptable or if there are good
alternatives other than emulating its behaviour manually in the custom
sentinel.

Thank you,

  Štěpán

[1] As indicated e.g. by https://github.com/search?q=internal-default-process-sentinel+language%3A%22Emacs+Lisp%22&type=Code