Daemon CapTP EPIPE on write

[kriskowal]

Describe the bug

Example https://github.com/endojs/endo/actions/runs/8806498315/job/24171474175

Daemon tests exercising CapTP occasionally exhibit a failure due to dangling bytes after closing a connection or EPIPE when writing a connection while shutting down. These occur most frequently for Windows CI, then Linux CI, and then rarely but occasionally in local development.

Steps to reproduce

Investigate above CI failure. The problem appears to occur due to timing during CapTP connection shutdown.

Expected behavior

Daemon should gracefully exit and should tolerate various patterns of disconnection.

Platform environment

All, with varying frequency.

Additional context

Screenshots