Add docs for TArg default methods (#535)

Author: bitfaster

BitFaster.Caching/IAsyncCache.cs

@@ -64,6 +64,7 @@ public interface IAsyncCache<K, V> : IEnumerable<KeyValuePair<K, V>>
         /// <param name="valueFactory">The factory function used to asynchronously generate a value for the key.</param>
         /// <param name="factoryArgument">An argument value to pass into valueFactory.</param>
         /// <returns>A task that represents the asynchronous GetOrAdd operation.</returns>
+        /// <remarks>The default implementation given here is the fallback that provides backwards compatibility for classes that implement ICache on prior versions</remarks>
         ValueTask<V> GetOrAddAsync<TArg>(K key, Func<K, TArg, Task<V>> valueFactory, TArg factoryArgument) => this.GetOrAddAsync(key, k => valueFactory(k, factoryArgument));
 
         /// <summary>

BitFaster.Caching/ICache.cs

@@ -65,6 +65,7 @@ public interface ICache<K, V> : IEnumerable<KeyValuePair<K, V>>
         /// <param name="factoryArgument">An argument value to pass into valueFactory.</param>
         /// <returns>The value for the key. This will be either the existing value for the key if the key is already 
         /// in the cache, or the new value if the key was not in the cache.</returns>
+        /// <remarks>The default implementation given here is the fallback that provides backwards compatibility for classes that implement ICache on prior versions</remarks>
         V GetOrAdd<TArg>(K key, Func<K, TArg, V> valueFactory, TArg factoryArgument) => this.GetOrAdd(key, k => valueFactory(k, factoryArgument));
 
         /// <summary>

BitFaster.Caching/IScopedAsyncCache.cs

@@ -69,6 +69,7 @@ public interface IScopedAsyncCache<K, V> : IEnumerable<KeyValuePair<K, Scoped<V>
         /// <param name="valueFactory">The factory function used to asynchronously generate a scoped value for the key.</param>
         /// <param name="factoryArgument"></param>
         /// <returns>A task that represents the asynchronous ScopedGetOrAdd operation.</returns>
+        /// <remarks>The default implementation given here is the fallback that provides backwards compatibility for classes that implement ICache on prior versions</remarks>
         ValueTask<Lifetime<V>> ScopedGetOrAddAsync<TArg>(K key, Func<K, TArg, Task<Scoped<V>>> valueFactory, TArg factoryArgument) => this.ScopedGetOrAddAsync(key, (k) => valueFactory(k, factoryArgument));
 #endif
 

BitFaster.Caching/IScopedCache.cs

@@ -72,6 +72,7 @@ public interface IScopedCache<K, V> : IEnumerable<KeyValuePair<K, Scoped<V>>> wh
         /// <returns>The lifetime for the value associated with the key. The lifetime will be either reference the 
         /// existing value for the key if the key is already in the cache, or the new value if the key was not in 
         /// the cache.</returns>
+        /// <remarks>The default implementation given here is the fallback that provides backwards compatibility for classes that implement ICache on prior versions</remarks>
         Lifetime<V> ScopedGetOrAdd<TArg>(K key, Func<K, TArg, Scoped<V>> valueFactory, TArg factoryArgument) => this.ScopedGetOrAdd(key, k => valueFactory(k, factoryArgument));
 #endif