[PATCH 0/4] MR6045: server: Reimplement mailslots using server-side I/O.

[Elizabeth Figura (＠zfigura)]

This fixes various corner cases.

This is not motivated by any particular application. However, the server-side
code seems at least as simple as the existing client-side code, is more
accurate, and removes a potential source of complication from any future work
involving asyncs.