Can checkpoint creation be parallel?

Hello:

Sorry for disturbing:

I have one question about checkponint . That is : can checkpoint be
parallel?

It is said that checkpoint will be activated according to either conditions:

1)After last checkpoint, checkpoint_timeout seconds passed.

2)When shared_buffers memory above checkpoint_segments size is filled with
data.

My experience is that :

There is only one checkpoint process there and works, and even when there
are many data created during transactions,

There will also be only one checkpoint process deal with it

(maybe background writer or some other server process will deal it)?

And also, I think when the above 1) or 2) activated checkpoint ,

after the checkpoint data creation, then the 1) and 2) value will be to
zero and calculated again.

So I think that checkpoint will not be created parallel.

Is my understanding right?

And if there are some official documentation from www.postgresql.org or
somewhere else, I'll be very appreciative.

Thanks!

Jian Gao