add caching for GetHeaderSplit MethodInfo

Author: smnsht

src/Http/Http.Extensions/src/RequestDelegateFactory.cs

@@ -52,6 +52,7 @@ public static partial class RequestDelegateFactory
     private static readonly MethodInfo ExecuteTaskResultOfTMethod = typeof(RequestDelegateFactory).GetMethod(nameof(ExecuteTaskResult), BindingFlags.NonPublic | BindingFlags.Static)!;
     private static readonly MethodInfo ExecuteValueResultTaskOfTMethod = typeof(RequestDelegateFactory).GetMethod(nameof(ExecuteValueTaskResult), BindingFlags.NonPublic | BindingFlags.Static)!;
     private static readonly MethodInfo ExecuteAwaitedReturnMethod = typeof(RequestDelegateFactory).GetMethod(nameof(ExecuteAwaitedReturn), BindingFlags.NonPublic | BindingFlags.Static)!;
+    private static readonly MethodInfo GetHeaderSplitMethod = typeof(ParsingHelpers).GetMethod(nameof(ParsingHelpers.GetHeaderSplit), BindingFlags.Public | BindingFlags.Static, [typeof(IHeaderDictionary), typeof(string)])!;
     private static readonly MethodInfo GetRequiredServiceMethod = typeof(ServiceProviderServiceExtensions).GetMethod(nameof(ServiceProviderServiceExtensions.GetRequiredService), BindingFlags.Public | BindingFlags.Static, new Type[] { typeof(IServiceProvider) })!;
     private static readonly MethodInfo GetServiceMethod = typeof(ServiceProviderServiceExtensions).GetMethod(nameof(ServiceProviderServiceExtensions.GetService), BindingFlags.Public | BindingFlags.Static, new Type[] { typeof(IServiceProvider) })!;
     private static readonly MethodInfo GetRequiredKeyedServiceMethod = typeof(ServiceProviderKeyedServiceExtensions).GetMethod(nameof(ServiceProviderKeyedServiceExtensions.GetRequiredKeyedService), BindingFlags.Public | BindingFlags.Static, new Type[] { typeof(IServiceProvider), typeof(object) })!;
@@ -1958,10 +1959,7 @@ private static Expression BindParameterFromExpression(
     private static Expression BindParameterFromProperty(ParameterInfo parameter, MemberExpression property, PropertyInfo itemProperty, string key, RequestDelegateFactoryContext factoryContext, string source)
     {
         var valueExpression = (source == "header" && parameter.ParameterType.IsArray)
-            ? Expression.Call(
-                typeof(ParsingHelpers).GetMethod(nameof(ParsingHelpers.GetHeaderSplit), BindingFlags.Public | BindingFlags.Static, [typeof(IHeaderDictionary), typeof(string)])!,
-                property,
-                Expression.Constant(key))
+            ? Expression.Call(GetHeaderSplitMethod, property, Expression.Constant(key))
             : GetValueFromProperty(property, itemProperty, key, GetExpressionType(parameter.ParameterType));
 
         return BindParameterFromValue(parameter, valueExpression, factoryContext, source);