# SignalR — Known Issues & Limitations

## Protocol

### PROTO-1: Server-side IsRawBytesData pre-serialize

**Status:** Planned removal
**Affects:** `AcWebSignalRHubBase.SendMessageToClient`

The server forwards the client's `IsRawBytesData` flag in the response `SignalParams`. This causes the protocol to return raw `byte[]` instead of deserializing. The original design pre-serialized on the server side, but with the zero-copy typed deserialization path (`SignalDataType`), this is redundant.

**Plan:** Remove `IsRawBytesData` forwarding from server response path. The client should use `SignalDataType` for typed deserialization and explicit `byte[]` type for raw data.

### PROTO-2: Parameter serialization is per-parameter

**Status:** Known performance concern
**Affects:** `SignalParams.SetParameterValues` / `GetParameterValues`

Each parameter is individually serialized via `ToBinary()` / `BinaryTo(Type)` — N context pool acquire/release cycles. For many small primitives (int, bool, string) the per-call overhead may exceed a single bulk serialization.

**Possible optimization:** Batch fast-path — single serialization context for all parameters. Benchmark first.

### PROTO-3: Parameter serialization is AcBinary only

**Status:** Limitation
**Affects:** `SignalParams.SetParameterValues` / `GetParameterValues`

Uses `ToBinary()` / `BinaryTo()` exclusively. JSON parameter support would require dispatching on `DataSerializerType` + `AcJsonSerializer` reference. Low priority — binary is the primary transport.

## Transport

### TRANS-1: BufferWriterChunkSize defaults to 64KB for SignalR

**Status:** Optimization opportunity
**Affects:** `AyCodeBinaryHubProtocol` default constructor, write path

The default `BufferWriterChunkSize` is 65536 (from `AcBinarySerializerOptions.Default`). For SignalR/Kestrel, 4096 aligns better with the transport's internal segment size, reducing latency-to-first-byte.

**Plan:** Set `BufferWriterChunkSize = 4096` in `AyCodeBinaryHubProtocol` default constructor. The options property already exists (`AcBinarySerializerOptions.BufferWriterChunkSize`). Non-SignalR paths keep 64KB default.

### TRANS-2: WebSocket buffer sizes are hardcoded

**Status:** Acceptable
**Affects:** `AcSignalRClientBase` connection setup

Transport max message size (30MB) and application buffer (30MB) are hardcoded. Sufficient for current payloads but not configurable per-deployment.

## DataSource

### DS-1: GetAll returns raw byte[] for populate/merge

**Status:** By design
**Affects:** `AcSignalRDataSource.LoadDataSourceAsync`

The `GetAll` path uses `IsRawBytesData = true` to receive raw `byte[]` from the protocol, then deserializes into the existing list via `PopulateMerge`. This avoids allocating a temporary `List<T>` for merge. The extra copy (pipe → byte[]) is the trade-off.

**Possible optimization:** Direct typed deserialization with merge support in the deserializer (PopulateMerge from `ReadOnlySequence<byte>`). Requires deserializer API changes.