add credit based mux window

client/config.go

@@ -29,10 +29,24 @@ const (
 	MuxData = 0x01
 	MuxFin  = 0x02
 	MuxRst  = 0x03
+	MuxWnd  = 0x04
 
 	FrameError = 0x7F
 
 	SaturationThreshold = 8
+
+	// Session-establishment feature flags (trailing VarInt on the Rekey message).
+	FlagStreamFC = 0x01
+
+	// Per-stream flow-control window bounds (bytes). The advertised window is the
+	// receiver's promise of how much un-credited DATA it will buffer per stream.
+	DefaultStreamWindow = 256 * 1024
+	MinStreamWindow     = 32 * 1024
+	MaxStreamWindow     = 8 << 20
+
+	// DataChunkSize caps a single DATA frame's payload so no stream monopolizes
+	// the shared worker connection for long.
+	DataChunkSize = 32 * 1024
 )
 
 // Mapping routes a registered pattern to a real destination.
@@ -44,11 +58,12 @@ type Mapping struct {
 
 // Config is the client configuration (PROTOCOL.md §9.2).
 type Config struct {
-	Server         string    `json:"server"`
-	PSK            string    `json:"psk"`
-	MaxConn        int       `json:"maxConn"`
-	PingIntervalMs int       `json:"pingIntervalMs"`
-	Mappings       []Mapping `json:"mappings"`
+	Server            string    `json:"server"`
+	PSK               string    `json:"psk"`
+	MaxConn           int       `json:"maxConn"`
+	PingIntervalMs    int       `json:"pingIntervalMs"`
+	StreamWindowBytes int       `json:"streamWindowBytes"` // per-stream receive window; 0 = default
+	Mappings          []Mapping `json:"mappings"`
 }
 
 // LoadConfig reads and validates a JSON config file.