Do we guarantee that the contents of buf passed to poll_write of AsyncWrite are the same?

[RealXuChe]

I'm implementing AsyncWrite for some struct. If poll_write returned Pending for the first poll, is it safe to suggest that the buf passed next time has the same content as the first-poll one?

Or, does the following buf's content passed before returning Ready only appends the previous one?

(Sorry for my bad English)

[Darksonn]

No. This is not guaranteed.