Re: Streaming I/O, vectored I/O (WIP)

I've written a new version of the vacuum streaming read user on top of
the rebased patch set [1]. It differs substantially from Andres' and
includes several refactoring patches that can apply on top of master.
As such, I've proposed those in a separate thread [2]. I noticed mac
and windows fail to build on CI for my branch with the streaming read
code. I haven't had a chance to investigate  -- but I must have done
something wrong on rebase.

- Melanie

[1] https://github.com/melanieplageman/postgres/tree/stepwise_vac_streaming_read
[2] https://www.postgresql.org/message-id/CAAKRu_Yf3gvXGcCnqqfoq0Q8LX8UM-e-qbm_B1LeZh60f8WhWA%40mail.gmail.com