daily update on 20250214 by nitload youmu, building syntax analysor, tough！

内核源代码/StgSharp.Common/Collections/PartialDictionary.cs

@@ -31,14 +31,15 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
+using System.Net.Http.Headers;
 using System.Text;
 
 namespace StgSharp.Collections
 {
     public partial class PartialDictionary<TKey, TValue> : IDictionary<TKey, TValue>
     {
-
         private readonly Dictionary<TKey, TValue> _source;
         private readonly HashSet<TKey> _keys;
         private readonly PartialDictionaryValues _values;
@@ -71,6 +72,23 @@ namespace StgSharp.Collections
             _values = new PartialDictionaryValues( this );
         }
 
+        public PartialDictionary(
+                Dictionary<TKey, TValue> source,
+                TKey[] index, IHashMultiplexer<TKey> multiplexer
+            )
+        {
+            _source = source;
+            _keys = new HashSet<TKey>(index);
+            foreach (TKey item in _keys)
+            {
+                if (!_source.ContainsKey(item))
+                {
+                    _source.Add(item, default!);
+                }
+            }
+            _values = new PartialDictionaryValues(this);
+        }
+
         public TValue this[ TKey key ]
         {
             get