7213ddfbf1
Real GEM sessions don't serialize requests — the host can have many
primaries outstanding, replies may arrive in any order, and both
peers can talk at once. Connection demuxes via system_bytes per
E37 §8.3; this commit pins the behaviour with four wire tests:
- 5 in-flight requests; equipment buffers all primaries before
replying — proves Connection holds the pending map correctly
even when no replies are coming.
- 7 pipelined primaries with synchronous in-handler replies;
every host callback fires with the correct function and stream.
- Bidirectional in-flight: host issues 3 primaries while equipment
issues 3 of its own; all 6 callbacks resolve with the right
replies.
- 100-burst sequential cycle; confirms the pending_requests_ map
doesn't leak entries (every reply delivered ⇒ map drained).
Closes #13 in the test-gap backlog.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>