Fix A: add Raw_multi_node_per_node_error_isolation test — two historized variables
(eqA/good→A.PV, eqB/bad→B.PV) in one Raw batch; per-tagname fake throws for B.PV,
returns a sample for A.PV; asserts errors[0]=Good+sample, errors[1]=Bad,
HistoryData[1]=null (no cross-slot leak), no exception escapes.
Fix B: collapse double ConcurrentDictionary lookup in ServeNode — TryGetHistorizedTagname
now captures `out var tagname` on the guard; the resolved tagname is threaded into the
read callback as a second parameter (Func<IHistorianDataSource, string, Task<HistorianRead>>),
removing the redundant ResolveTagname helper (deleted) and the tiny race window between
the check and the second lookup. All three call-sites (Raw/Processed/AtTime) updated.
Fix C: rewrite the IsReadModified comment at NodeManagerHistoryReadTests.cs:102 — the
SDK's ReadRawModifiedDetails.Initialize() sets m_isReadModified=true (generated ctor body
in Opc.Ua.DataTypes.cs), so the default IS true; the test must explicitly clear it to
false for a plain raw read. Previous comment said the same thing but imprecisely; now
cites the SDK mechanism (Initialize() call in the public ctor).
Joseph Doherty
059f18bdad