riversong code showcase

Source/Engine/Collections/IMultiDictionary.cs

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+using System.Collections.Generic;
+
+namespace DanieleMarotta.RiversongCodeShowcase
+{
+    public interface IMultiDictionary<K, V, C> : IEnumerable<KeyValuePair<K, V>> where C : ICollection<V>
+    {
+        C this[K key] { get; }
+
+        Dictionary<K, C>.KeyCollection Keys { get; }
+
+        int KeyCount { get; }
+
+        int ValueCount { get; }
+
+        int Count(K key);
+
+        bool Add(K key, V value);
+
+        bool Remove(K key, V value);
+
+        bool Remove(V value);
+
+        void Clear(K key);
+
+        void Clear();
+
+        bool ContainsKey(K key);
+
+        bool ContainsValue(K key, V value);
+
+        bool ContainsValue(V value);
+
+        bool TryGetValues(K key, out C values);
+    }
+}