Add SupportsPooling/IsLegacyRoute properties to RouteConnection and
GetLegacyRoute/GetLegacyRoutes/HasLegacyRoutes to RouteManager. Update
GetRouteForAccount to fall back to legacy routes when no dedicated or
pool-capable route is available, matching Go route.go getRoutesExcludePool.
Add NegotiatePoolSize static method and NegotiatedPoolSize property to
RouteConnection, and ConfiguredPoolSize / GetEffectivePoolSize to
RouteManager. Includes 14 tests covering negotiation semantics, backward
compatibility (zero means no pooling), default state, and deterministic
pool index computation.
Add RemoveRoute, RemoveAllRoutesExcept, RegisterRoute (internal), and
DetectClusterSplit to RouteManager with ClusterSplitResult record, plus
10 tests covering partition detection and route removal behavior.
Add _accountRoutes ConcurrentDictionary to RouteManager with full
CRUD API: RegisterAccountRoute, UnregisterAccountRoute,
GetDedicatedAccountRoute, HasDedicatedRoute,
GetAccountsWithDedicatedRoutes, and DedicatedRouteCount property.
Update GetRouteForAccount to check dedicated routes before falling
back to pool-based selection. Add 10 unit tests in AccountRouteTests.
D2: Add FNV-1a-based ComputeRoutePoolIdx to RouteManager matching Go's
route.go:533-545, with PoolIndex on RouteConnection and account-aware
ForwardRoutedMessageAsync that routes to the correct pool connection.
D3: Replace DeflateStream with IronSnappy in RouteCompressionCodec, add
RouteCompressionLevel enum, NegotiateCompression, and IsCompressed
detection. 17 new tests (6 pool + 11 compression), all passing.
