perf(h2): increase header table size to 64KB and enable Huffman encoding

Author: st0o0

src/TurboHTTP/Http2Options.cs

@@ -48,7 +48,7 @@ public sealed class Http2Options
     /// Advertised via SETTINGS_HEADER_TABLE_SIZE in the connection preface.
     /// Default is 4,096 (RFC 7541 default).
     /// </summary>
-    public int HeaderTableSize { get; set; } = 4_096;
+    public int HeaderTableSize { get; set; } = 65_536;
 
     /// <summary>
     /// Maximum number of reconnect attempts when a TCP connection drops with in-flight requests.

src/TurboHTTP/Protocol/Http2/StateMachine.cs

@@ -60,7 +60,7 @@ public StateMachine(TurboClientOptions options, IStageOperations ops)
         _tracker = new StreamTracker(1, options.Http2.MaxConcurrentStreams);
         _connection = new ConnectionState(options.Http2.InitialConnectionWindowSize,
             options.Http2.InitialStreamWindowSize);
-        _requestEncoder = new RequestEncoder(maxFrameSize: 16_384);
+        _requestEncoder = new RequestEncoder(useHuffman: true, maxFrameSize: 16_384);
         _statePoolCapacity = Math.Min(
             _tracker.MaxConcurrentStreams > 0 ? _tracker.MaxConcurrentStreams : 100,
             MaxStatePoolCapacity);