Captured the native 2023 R2 client's gRPC event send (new capture-send-event
harness scenario): it rides HistoryService.AddStreamValues with the SAME "OS"
(0x534F) storage-sample buffer the WCF path already uses (HistorianEventWrite-
Protocol) — confirming "no distinct RPC", and that it is NOT the historical
write's "ON" buffer. Diffed the write-enabled vs read-only v8 Event open: byte-
identical apart from per-session crypto, so the existing OpenSession event path
is reused unchanged.
So SendEvent-over-gRPC was pure assembly of proven parts:
- HistorianGrpcEventWriteOrchestrator = v8 Event open + CM_EVENT registration
(UpdC3/RegisterTags/EnsureTags) + AddStreamValues(OS buffer).
- HistorianClient.SendEventAsync now routes to it for RemoteGrpc (WCF otherwise).
Live-validated end-to-end against the 2023 R2 server: pure-managed SDK send →
AddStreamValues BSuccess=true → the event reads back from the server (markers
confirmed in returned event rows). The native gRPC RegisterTags(24B) +
EnsureTags(86B) byte-match our serializers (new GrpcEventSendProtocolTests
golden, closing the 83-vs-86 EnsureTags question). Gated live test
SendEventAsync_OverGrpc_AcceptsEvent (opt-in HISTORIAN_GRPC_EVENT_SEND=1).
331 offline tests pass.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Joseph Doherty
afc7c4bf96