namespace System.Runtime.CompilerServices { [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct | AttributeTargets.Enum | AttributeTargets.Interface | AttributeTargets.Delegate, Inherited = false, AllowMultiple = false)] public sealed class AsyncMethodBuilderAttribute : Attribute { public Type BuilderType { get; } public AsyncMethodBuilderAttribute(Type builderType) { BuilderType = builderType; } } }